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pkgs/development/compilers/gcc/ng/15/gcc/fix-collect2-paths.diff

@@ -0,0 +1,315 @@
+diff --git a/gcc/collect2.cc b/gcc/collect2.cc
+index 268ac378b9c..8a5c606075a 100644
+--- a/gcc/collect2.cc
++++ b/gcc/collect2.cc
+@@ -327,7 +327,7 @@ static void write_aix_file (FILE *, struct id *);
+ static char *resolve_lib_name (const char *);
+ #endif
+ static char *extract_string (const char **);
+-static void post_ld_pass (bool);
++static void post_ld_pass (bool, bool);
+ static void process_args (int *argcp, char **argv);
+ 
+ /* Enumerations describing which pass this is for scanning the
+@@ -513,12 +513,10 @@ is_ctor_dtor (const char *s)
+ 
+ static struct path_prefix cpath, path;
+ 
+-#ifdef CROSS_DIRECTORY_STRUCTURE
+ /* This is the name of the target machine.  We use it to form the name
+    of the files to execute.  */
+ 
+ static const char *const target_machine = TARGET_MACHINE;
+-#endif
+ 
+ /* Search for NAME using prefix list PPREFIX.  We only look for executable
+    files.
+@@ -577,7 +575,7 @@ add_lto_object (struct lto_object_list *list, const char *name)
+ 
+ static void
+ maybe_run_lto_and_relink (char **lto_ld_argv, char **object_lst,
+-			  const char **object, bool force)
++			  const char **object, bool force, bool is_cross_compiler)
+ {
+   const char **object_file = CONST_CAST2 (const char **, char **, object_lst);
+ 
+@@ -722,7 +720,7 @@ maybe_run_lto_and_relink (char **lto_ld_argv, char **object_lst,
+ 		    "ld_args");
+       /* We assume that temp files were created, and therefore we need to take
+          that into account (maybe run dsymutil).  */
+-      post_ld_pass (/*temp_file*/true);
++      post_ld_pass (/*temp_file*/true, is_cross_compiler);
+       free (lto_ld_argv);
+ 
+       maybe_unlink_list (lto_o_files);
+@@ -734,10 +732,10 @@ maybe_run_lto_and_relink (char **lto_ld_argv, char **object_lst,
+       fork_execute ("ld", lto_ld_argv, HAVE_GNU_LD && at_file_supplied,
+ 		    "ld_args");
+       /* No LTO objects were found, so no new temp file.  */
+-      post_ld_pass (/*temp_file*/false);
++      post_ld_pass (/*temp_file*/false, is_cross_compiler);
+     }
+   else
+-    post_ld_pass (false); /* No LTO objects were found, no temp file.  */
++    post_ld_pass (false, is_cross_compiler); /* No LTO objects were found, no temp file.  */
+ }
+ /* Entry point for linker invoation.  Called from main in collect2.cc.
+    LD_ARGV is an array of arguments for the linker.  */
+@@ -799,33 +797,14 @@ main (int argc, char **argv)
+   static const char *const gstrip_suffix = "gstrip";
+ 
+   const char *full_ld_suffixes[USE_LD_MAX];
+-#ifdef CROSS_DIRECTORY_STRUCTURE
+-  /* If we look for a program in the compiler directories, we just use
+-     the short name, since these directories are already system-specific.
+-     But it we look for a program in the system directories, we need to
+-     qualify the program name with the target machine.  */
+-
+-  const char *const full_nm_suffix =
+-    concat (target_machine, "-", nm_suffix, NULL);
+-  const char *const full_gnm_suffix =
+-    concat (target_machine, "-", gnm_suffix, NULL);
+-#ifdef LDD_SUFFIX
+-  const char *const full_ldd_suffix =
+-    concat (target_machine, "-", ldd_suffix, NULL);
+-#endif
+-  const char *const full_strip_suffix =
+-    concat (target_machine, "-", strip_suffix, NULL);
+-  const char *const full_gstrip_suffix =
+-    concat (target_machine, "-", gstrip_suffix, NULL);
+-#else
++  const char *full_nm_suffix;
++  const char *full_gnm_suffix;
++  const char *full_strip_suffix;
++  const char *full_gstrip_suffix;
++
+ #ifdef LDD_SUFFIX
+-  const char *const full_ldd_suffix	= ldd_suffix;
++  const char *full_ldd_suffix;
+ #endif
+-  const char *const full_nm_suffix	= nm_suffix;
+-  const char *const full_gnm_suffix	= gnm_suffix;
+-  const char *const full_strip_suffix	= strip_suffix;
+-  const char *const full_gstrip_suffix	= gstrip_suffix;
+-#endif /* CROSS_DIRECTORY_STRUCTURE */
+ 
+   const char *arg;
+   FILE *outf;
+@@ -840,6 +819,7 @@ main (int argc, char **argv)
+   const char **ld1;
+   bool use_plugin = false;
+   bool use_collect_ld = false;
++  bool is_cross_compiler = false;
+ 
+   /* The kinds of symbols we will have to consider when scanning the
+      outcome of a first pass link.  This is ALL to start with, then might
+@@ -864,17 +844,6 @@ main (int argc, char **argv)
+ #endif
+   int i;
+ 
+-  for (i = 0; i < USE_LD_MAX; i++)
+-#ifdef CROSS_DIRECTORY_STRUCTURE
+-    /* lld and mold are platform-agnostic and not prefixed with target
+-       triple.  */
+-    if (!(i == USE_LLD_LD || i == USE_MOLD_LD))
+-      full_ld_suffixes[i] = concat (target_machine, "-", ld_suffixes[i],
+-				    NULL);
+-    else
+-#endif
+-      full_ld_suffixes[i] = ld_suffixes[i];
+-
+   p = argv[0] + strlen (argv[0]);
+   while (p != argv[0] && !IS_DIR_SEPARATOR (p[-1]))
+     --p;
+@@ -1050,6 +1019,65 @@ main (int argc, char **argv)
+   prefix_from_env ("COMPILER_PATH", &cpath);
+   prefix_from_env ("PATH", &path);
+ 
++  /* Determine the full path name of the C compiler to use.  */
++  c_file_name = getenv ("COLLECT_GCC");
++  if (c_file_name == 0)
++    {
++      c_file_name = concat (target_machine, "-gcc", NULL);
++      p = find_a_file (&cpath, c_file_name, X_OK);
++      if (p == 0)
++        p = find_a_file (&path, c_file_name, X_OK);
++
++      if (p == 0) {
++        c_file_name = "gcc";
++        p = find_a_file (&cpath, c_file_name, X_OK);
++        if (p == 0)
++          p = find_a_file (&path, c_file_name, X_OK);
++      }
++    }
++  else
++    {
++      p = find_a_file (&cpath, c_file_name, X_OK);
++
++      /* Here it should be safe to use the system search path since we should have
++        already qualified the name of the compiler when it is needed.  */
++      if (p == 0)
++        p = find_a_file (&path, c_file_name, X_OK);
++    }
++
++  if (p)
++    c_file_name = p;
++
++  if (c_file_name) {
++    is_cross_compiler = strncmp(basename(c_file_name), target_machine, strlen(target_machine)) == 0;
++  }
++
++  for (i = 0; i < USE_LD_MAX; i++)
++    /* lld and mold are platform-agnostic and not prefixed with target
++       triple.  */
++    if (!(i == USE_LLD_LD || i == USE_MOLD_LD) && is_cross_compiler)
++      full_ld_suffixes[i] = concat (target_machine, "-", ld_suffixes[i],
++				    NULL);
++    else
++      full_ld_suffixes[i] = ld_suffixes[i];
++
++  full_nm_suffix =
++    is_cross_compiler ? concat (target_machine, "-", nm_suffix, NULL) : nm_suffix;
++
++  full_gnm_suffix =
++    is_cross_compiler ? concat (target_machine, "-", gnm_suffix, NULL) : gnm_suffix;
++
++  full_strip_suffix =
++    is_cross_compiler ? concat (target_machine, "-", strip_suffix, NULL) : strip_suffix;
++
++  full_gstrip_suffix =
++    is_cross_compiler ? concat (target_machine, "-", gstrip_suffix, NULL) : gstrip_suffix;
++
++#ifdef LDD_SUFFIX
++  full_ldd_suffix =
++    is_cross_compiler ? concat (target_machine, "-", ldd_suffix, NULL) : ldd_suffix;
++#endif
++
+   /* Try to discover a valid linker/nm/strip to use.  */
+ 
+   /* Maybe we know the right file to use (if not cross).  */
+@@ -1139,27 +1167,6 @@ main (int argc, char **argv)
+   if (strip_file_name == 0)
+     strip_file_name = find_a_file (&path, full_strip_suffix, X_OK);
+ 
+-  /* Determine the full path name of the C compiler to use.  */
+-  c_file_name = getenv ("COLLECT_GCC");
+-  if (c_file_name == 0)
+-    {
+-#ifdef CROSS_DIRECTORY_STRUCTURE
+-      c_file_name = concat (target_machine, "-gcc", NULL);
+-#else
+-      c_file_name = "gcc";
+-#endif
+-    }
+-
+-  p = find_a_file (&cpath, c_file_name, X_OK);
+-
+-  /* Here it should be safe to use the system search path since we should have
+-     already qualified the name of the compiler when it is needed.  */
+-  if (p == 0)
+-    p = find_a_file (&path, c_file_name, X_OK);
+-
+-  if (p)
+-    c_file_name = p;
+-
+   *ld1++ = *ld2++ = ld_file_name;
+ 
+   /* Make temp file names.  */
+@@ -1595,6 +1602,8 @@ main (int argc, char **argv)
+ 	       (c_file ? c_file : "not found"));
+       fprintf (stderr, "o_file              = %s\n",
+ 	       (o_file ? o_file : "not found"));
++      fprintf (stderr, "is_cross_compiler   = %s\n",
++          (is_cross_compiler ? "yes" : "no"));
+ 
+       ptr = getenv ("COLLECT_GCC_OPTIONS");
+       if (ptr)
+@@ -1644,9 +1653,9 @@ main (int argc, char **argv)
+ 	  maybe_unlink (export_file);
+ #endif
+ 	if (lto_mode != LTO_MODE_NONE)
+-	  maybe_run_lto_and_relink (ld1_argv, object_lst, object, false);
++	  maybe_run_lto_and_relink (ld1_argv, object_lst, object, false, is_cross_compiler);
+ 	else
+-	  post_ld_pass (/*temp_file*/false);
++	  post_ld_pass (/*temp_file*/false, is_cross_compiler);
+ 
+ 	return 0;
+       }
+@@ -1698,7 +1707,7 @@ main (int argc, char **argv)
+ 	do_link (ld1_argv, "ld1_args");
+ 
+       if (lto_mode)
+-        maybe_run_lto_and_relink (ld1_argv, object_lst, object, false);
++        maybe_run_lto_and_relink (ld1_argv, object_lst, object, false, is_cross_compiler);
+ 
+       /* Strip now if it was requested on the command line.  */
+       if (strip_flag)
+@@ -1716,7 +1725,7 @@ main (int argc, char **argv)
+ #ifdef COLLECT_EXPORT_LIST
+       maybe_unlink (export_file);
+ #endif
+-      post_ld_pass (/*temp_file*/false);
++      post_ld_pass (/*temp_file*/false, is_cross_compiler);
+       return 0;
+     }
+ 
+@@ -1799,15 +1808,15 @@ main (int argc, char **argv)
+   do_link (ld2_argv, "ld2_args");
+ 
+   if (lto_mode)
+-    maybe_run_lto_and_relink (ld2_argv, object_lst, object, false);
++    maybe_run_lto_and_relink (ld2_argv, object_lst, object, false, is_cross_compiler);
+ #else
+   /* Otherwise, simply call ld because link is already done.  */
+   if (lto_mode)
+-    maybe_run_lto_and_relink (ld2_argv, object_lst, object, true);
++    maybe_run_lto_and_relink (ld2_argv, object_lst, object, true, is_cross_compiler);
+   else
+     {
+       fork_execute ("ld", ld2_argv, HAVE_GNU_LD && at_file_supplied, "ld_args");
+-      post_ld_pass (/*temp_file*/false);
++      post_ld_pass (/*temp_file*/false, is_cross_compiler);
+     }
+ 
+   /* Let scan_prog_file do any final mods (OSF/rose needs this for
+@@ -3020,7 +3029,7 @@ process_args (int *argcp, char **argv) {
+ }
+ 
+ static void
+-do_dsymutil (const char *output_file) {
++do_dsymutil (const char *output_file, bool is_cross_compiler) {
+   const char *dsymutil = 0;
+   struct pex_obj *pex;
+   char **real_argv = XCNEWVEC (char *, verbose ? 4 : 3);
+@@ -3032,11 +3041,7 @@ do_dsymutil (const char *output_file) {
+    here is consistent with the way other installations work (and one can
+    always symlink a multitarget dsymutil with a target-specific name).  */
+   const char *dsname = "dsymutil";
+-#ifdef CROSS_DIRECTORY_STRUCTURE
+-  const char *qname = concat (target_machine, "-", dsname, NULL);
+-#else
+-  const char *qname = dsname;
+-#endif
++  const char *qname = is_cross_compiler ? concat (target_machine, "-", dsname, NULL) : dsname;
+ #ifdef DEFAULT_DSYMUTIL
+   /* Configured default takes priority.  */
+   if (dsymutil == 0 && access (DEFAULT_DSYMUTIL, X_OK) == 0)
+@@ -3071,14 +3076,14 @@ do_dsymutil (const char *output_file) {
+ }
+ 
+ static void
+-post_ld_pass (bool temp_file) {
++post_ld_pass (bool temp_file, bool is_cross_compiler) {
+   if (!(temp_file && flag_idsym) && !flag_dsym)
+     return;
+ 
+-  do_dsymutil (output_file);
++  do_dsymutil (output_file, is_cross_compiler);
+ }
+ #else
+ static void
+ process_args (int *argcp ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED) { }
+-static void post_ld_pass (bool temp_file ATTRIBUTE_UNUSED) { }
++static void post_ld_pass (bool temp_file ATTRIBUTE_UNUSED, bool is_cross_compiler ATTRIBUTE_UNUSED) { }
+ #endif

pkgs/development/compilers/gcc/ng/15/libgcc/force-regular-dirs.patch

@@ -0,0 +1,49 @@
+From bb3277895d3bd77bcacb7c489ebb1390478bbc12 Mon Sep 17 00:00:00 2001
+From: John Ericson <John.Ericson@Obsidian.Systems>
+Date: Thu, 17 Jul 2025 11:00:07 -0400
+Subject: [PATCH 2/2] Force regular dirs
+
+Override directories in libgcc so they are normal $out/lib and
+$dev/include. This is not suitable for upstreaming, but is done on top
+of a different patch which is, and which makes this smaller.
+
+---
+ libgcc/Makefile.in  | 6 +++---
+ libgcc/configure.ac | 3 ---
+ 2 files changed, 3 insertions(+), 6 deletions(-)
+
+diff --git a/libgcc/Makefile.in b/libgcc/Makefile.in
+index 4661c36703d..986cd035148 100644
+--- a/libgcc/Makefile.in
++++ b/libgcc/Makefile.in
+@@ -202,10 +202,10 @@ STRIP = @STRIP@
+ STRIP_FOR_TARGET = $(STRIP)
+ 
+ # Used to install the shared libgcc.
+-slibdir = @slibdir@
++slibdir = $(libdir)
+ # Maybe used for DLLs on Windows targets.
+-toolexecdir = @toolexecdir@
+-toolexeclibdir = @toolexeclibdir@
++toolexecdir = $(bindir)
++toolexeclibdir = $(libdir)
+ 
+ export AR_FOR_TARGET
+ export AR_CREATE_FOR_TARGET
+diff --git a/libgcc/configure.ac b/libgcc/configure.ac
+index 5fdac5d95f2..89044cb65c9 100644
+--- a/libgcc/configure.ac
++++ b/libgcc/configure.ac
+@@ -479,9 +479,6 @@ if test x"$enable_as_accelerator_for" != x; then
+   accel_dir_suffix=/accel/${target_noncanonical}
+   real_host_noncanonical=${enable_as_accelerator_for}
+ fi
+-# Directory in which the compiler finds libraries etc.
+-libdir=${orig_libdir}/gcc/${real_host_noncanonical}/'$(version)'${accel_dir_suffix}
+-includedir=${libdir}/include
+ 
+ if test x"$enable_offload_targets" != x; then
+   extra_parts="${extra_parts} crtoffloadbegin.o crtoffloadend.o"
+-- 
+2.47.2
+

pkgs/development/compilers/gcc/ng/15/libgfortran/force-regular-dirs.patch

@@ -0,0 +1,53 @@
+From 7a0c8ca8872a73c6886940448ba9b3203b13268d Mon Sep 17 00:00:00 2001
+From: John Ericson <git@JohnEricson.me>
+Date: Mon, 21 Jul 2025 11:42:13 -0400
+Subject: [PATCH] libgfortran: Force regular include/lib dir
+
+---
+ libgfortran/Makefile.am | 13 +++++--------
+ 1 file changed, 5 insertions(+), 8 deletions(-)
+
+diff --git a/libgfortran/Makefile.am b/libgfortran/Makefile.am
+index 21b35c76a06..3d38cde5b42 100644
+--- a/libgfortran/Makefile.am
++++ b/libgfortran/Makefile.am
+@@ -42,14 +42,13 @@ extra_darwin_ldflags_libgfortran += -Wc,-nodefaultrpaths
+ extra_darwin_ldflags_libgfortran += -Wl,-rpath,@loader_path
+ endif
+ 
+-gfor_c_HEADERS = ISO_Fortran_binding.h
+-gfor_cdir = $(libdir)/gcc/$(target_alias)/$(gcc_version)/include
++include_HEADERS = ISO_Fortran_binding.h
+ 
+ LTLDFLAGS = $(shell $(SHELL) $(top_srcdir)/../libtool-ldflags $(LDFLAGS)) \
+ 	    $(lt_host_flags)
+ 
+-toolexeclib_LTLIBRARIES = libgfortran.la
+-toolexeclib_DATA = libgfortran.spec
++lib_LTLIBRARIES = libgfortran.la
++toolexeclib_DATA = libgfortran.spec # needs "exec" in name
+ libgfortran_la_LINK = $(LINK) $(libgfortran_la_LDFLAGS)
+ libgfortran_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
+ 	$(LTLDFLAGS) $(LIBQUADLIB) ../libbacktrace/libbacktrace.la \
+@@ -58,16 +57,14 @@ libgfortran_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version`
+ 	$(version_arg) -Wc,-shared-libgcc
+ libgfortran_la_DEPENDENCIES = $(version_dep) libgfortran.spec $(LIBQUADLIB_DEP)
+ 
+-cafexeclib_LTLIBRARIES = libcaf_single.la
+-cafexeclibdir = $(libdir)/gcc/$(target_alias)/$(gcc_version)$(MULTISUBDIR)
++lib_LTLIBRARIES += libcaf_single.la
+ libcaf_single_la_SOURCES = caf/single.c
+ libcaf_single_la_LDFLAGS = -static
+ libcaf_single_la_DEPENDENCIES = caf/libcaf.h
+ libcaf_single_la_LINK = $(LINK) $(libcaf_single_la_LDFLAGS)
+ 
+ if IEEE_SUPPORT
+-fincludedir = $(libdir)/gcc/$(target_alias)/$(gcc_version)$(MULTISUBDIR)/finclude
+-nodist_finclude_HEADERS = ieee_arithmetic.mod ieee_exceptions.mod ieee_features.mod
++nodist_include_HEADERS = ieee_arithmetic.mod ieee_exceptions.mod ieee_features.mod
+ endif
+ 
+ ## io.h conflicts with a system header on some platforms, so
+-- 
+2.47.2
+

pkgs/development/compilers/gcc/ng/15/libssp/force-regular-dirs.patch

@@ -0,0 +1,30 @@
+From e7dac0e90f3e4363d858a6f147d7cc4f62815dd6 Mon Sep 17 00:00:00 2001
+From: John Ericson <John.Ericson@Obsidian.Systems>
+Date: Fri, 18 Jul 2025 16:54:17 -0400
+Subject: [PATCH 3/3] Force regular dirs
+
+Override directories in libssp so they are normal $out/lib and
+$dev/include. This is not suitable for upstreaming, but is done on top
+of a different patch which is, and which makes this smaller.
+---
+ libssp/configure.ac | 4 ----
+ 1 file changed, 4 deletions(-)
+
+diff --git a/libssp/configure.ac b/libssp/configure.ac
+index 5b9fa4fbecc..f1723dc33ce 100644
+--- a/libssp/configure.ac
++++ b/libssp/configure.ac
+@@ -207,10 +207,6 @@ esac
+ AC_SUBST(toolexecdir)
+ AC_SUBST(toolexeclibdir)
+ 
+-# Directory in which the compiler finds libraries etc.
+-libdir='$(toolexeclibdir)'
+-includedir=${orig_libdir}/gcc/${host_noncanonical}/'$(version)/include'
+-
+ if test ${multilib} = yes; then
+   multilib_arg="--enable-multilib"
+ else
+-- 
+2.47.2
+

pkgs/development/compilers/gcc/ng/15/libstdcxx/force-regular-dirs.patch

@@ -0,0 +1,120 @@
+From db427c55334dd2edc11397d3a92d55dc9c06d1c3 Mon Sep 17 00:00:00 2001
+From: John Ericson <git@JohnEricson.me>
+Date: Sun, 20 Jul 2025 14:20:00 -0400
+Subject: [PATCH] libstdc++: Force regular include/lib dir
+
+Delete a bunch of unneeded logic to do this.
+---
+ libstdc++-v3/acinclude.m4        | 80 ++------------------------------
+ libstdc++-v3/include/Makefile.am |  2 +-
+ 2 files changed, 4 insertions(+), 78 deletions(-)
+
+diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
+index a0094c2dd95..a0718dff394 100644
+--- a/libstdc++-v3/acinclude.m4
++++ b/libstdc++-v3/acinclude.m4
+@@ -727,85 +727,11 @@ dnl
+ dnl This logic must match gcc/configure.ac's setting of gcc_gxx_include_dir.
+ dnl config/gxx-include-dir.m4 must be kept consistant with this as well.
+ AC_DEFUN([GLIBCXX_EXPORT_INSTALL_INFO], [
+-  glibcxx_toolexecdir=no
+-  glibcxx_toolexeclibdir=no
++  glibcxx_toolexecdir='$(libdir)'
++  glibcxx_toolexeclibdir='$(libdir)'
++  gxx_include_dir='$(includedir)'
+   glibcxx_prefixdir=$prefix
+ 
+-  AC_MSG_CHECKING([for gxx-include-dir])
+-  AC_ARG_WITH([gxx-include-dir],
+-    AC_HELP_STRING([--with-gxx-include-dir=DIR],
+-		   [installation directory for include files]),
+-    [case "$withval" in
+-      yes) AC_MSG_ERROR([Missing directory for --with-gxx-include-dir]) ;;
+-      no)  gxx_include_dir=no ;;
+-      *)   gxx_include_dir=$withval ;;
+-     esac],
+-    [gxx_include_dir=no])
+-  AC_MSG_RESULT($gxx_include_dir)
+-
+-  AC_MSG_CHECKING([for --enable-version-specific-runtime-libs])
+-  AC_ARG_ENABLE([version-specific-runtime-libs],
+-    AC_HELP_STRING([--enable-version-specific-runtime-libs],
+-		   [Specify that runtime libraries should be installed in a compiler-specific directory]),
+-    [case "$enableval" in
+-      yes) version_specific_libs=yes ;;
+-      no)  version_specific_libs=no ;;
+-      *)   AC_MSG_ERROR([Unknown argument to enable/disable version-specific libs]);;
+-     esac],
+-    [version_specific_libs=no])
+-  AC_MSG_RESULT($version_specific_libs)
+-
+-  GCC_WITH_TOOLEXECLIBDIR
+-
+-  # Default case for install directory for include files.
+-  if test $version_specific_libs = no && test $gxx_include_dir = no; then
+-    gxx_include_dir='include/c++/${gcc_version}'
+-    if test -n "$with_cross_host" &&
+-       test x"$with_cross_host" != x"no"; then
+-      gxx_include_dir='${prefix}/${target_alias}/'"$gxx_include_dir"
+-    else
+-      gxx_include_dir='${prefix}/'"$gxx_include_dir"
+-    fi
+-  fi
+-
+-  # Version-specific runtime libs processing.
+-  if test $version_specific_libs = yes; then
+-    # Need the gcc compiler version to know where to install libraries
+-    # and header files if --enable-version-specific-runtime-libs option
+-    # is selected.  FIXME: these variables are misnamed, there are
+-    # no executables installed in _toolexecdir or _toolexeclibdir.
+-    if test x"$gxx_include_dir" = x"no"; then
+-      gxx_include_dir='${libdir}/gcc/${host_alias}/${gcc_version}/include/c++'
+-    fi
+-    glibcxx_toolexecdir='${libdir}/gcc/${host_alias}'
+-    glibcxx_toolexeclibdir='${toolexecdir}/${gcc_version}$(MULTISUBDIR)'
+-  fi
+-
+-  # Calculate glibcxx_toolexecdir, glibcxx_toolexeclibdir
+-  # Install a library built with a cross compiler in tooldir, not libdir.
+-  if test x"$glibcxx_toolexecdir" = x"no"; then
+-    if test -n "$with_cross_host" &&
+-       test x"$with_cross_host" != x"no"; then
+-      glibcxx_toolexecdir='${exec_prefix}/${host_alias}'
+-      case ${with_toolexeclibdir} in
+-	no)
+-	  glibcxx_toolexeclibdir='${toolexecdir}/lib'
+-	  ;;
+-	*)
+-	  glibcxx_toolexeclibdir=${with_toolexeclibdir}
+-	  ;;
+-      esac
+-    else
+-      glibcxx_toolexecdir='${libdir}/gcc/${host_alias}'
+-      glibcxx_toolexeclibdir='${libdir}'
+-    fi
+-    multi_os_directory=`$CXX -print-multi-os-directory`
+-    case $multi_os_directory in
+-      .) ;; # Avoid trailing /.
+-      *) glibcxx_toolexeclibdir=$glibcxx_toolexeclibdir/$multi_os_directory ;;
+-    esac
+-  fi
+-
+   AC_MSG_CHECKING([for install location])
+   AC_MSG_RESULT($gxx_include_dir)
+ 
+diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
+index 537774c2668..c0bfeb43b44 100644
+--- a/libstdc++-v3/include/Makefile.am
++++ b/libstdc++-v3/include/Makefile.am
+@@ -1048,7 +1048,7 @@ endif
+ 
+ host_srcdir = ${glibcxx_srcdir}/$(OS_INC_SRCDIR)
+ host_builddir = ./${host_alias}/bits
+-host_installdir = ${gxx_include_dir}/${host_alias}$(MULTISUBDIR)/bits
++host_installdir = ${gxx_include_dir}/bits
+ host_headers = \
+ 	${host_srcdir}/ctype_base.h \
+ 	${host_srcdir}/ctype_inline.h \
+-- 
+2.47.2
+

pkgs/development/compilers/gcc/ng/README.md

@@ -0,0 +1,3 @@
+# GCC Next-Generation
+
+Experimental split GCC package set based on the LLVM package set design.

pkgs/development/compilers/gcc/ng/common/common-let.nix

@@ -0,0 +1,47 @@
+{
+  lib,
+  fetchurl ? null,
+  fetchgit ? null,
+  release_version ? null,
+  gitRelease ? null,
+  officialRelease ? null,
+  monorepoSrc' ? null,
+  version ? null,
+}@args:
+
+rec {
+  gcc_meta = {
+    license = with lib.licenses; [ gpl3Plus ];
+    teams = [ lib.teams.gcc ];
+  };
+
+  releaseInfo =
+    if gitRelease != null then
+      rec {
+        original = gitRelease;
+        release_version = args.version or original.version;
+        version = gitRelease.rev-version;
+      }
+    else
+      rec {
+        original = officialRelease;
+        release_version = args.version or original.version;
+        version =
+          if original ? candidate then "${release_version}-${original.candidate}" else release_version;
+      };
+
+  monorepoSrc =
+    if monorepoSrc' != null then
+      monorepoSrc'
+    else if gitRelease != null then
+      fetchgit {
+        url = "https://gcc.gnu.org/git/gcc.git";
+        inherit (gitRelease) rev;
+        hash = releaseInfo.original.sha256;
+      }
+    else
+      fetchurl {
+        url = "mirror://gcc/releases/gcc-${releaseInfo.version}/gcc-${releaseInfo.version}.tar.xz";
+        hash = releaseInfo.original.sha256;
+      };
+}

pkgs/development/compilers/gcc/ng/common/default.nix

@@ -0,0 +1,235 @@
+{
+  lib,
+  newScope,
+  stdenv,
+  overrideCC,
+  fetchgit,
+  fetchurl,
+  gitRelease ? null,
+  officialRelease ? null,
+  monorepoSrc ? null,
+  version ? null,
+  patchesFn ? lib.id,
+  wrapCCWith,
+  binutilsNoLibc,
+  binutils,
+  buildGccPackages,
+  targetGccPackages,
+  makeScopeWithSplicing',
+  otherSplices,
+  ...
+}@args:
+
+assert lib.assertMsg (lib.xor (gitRelease != null) (officialRelease != null)) (
+  "must specify `gitRelease` or `officialRelease`"
+  + (lib.optionalString (gitRelease != null) " — not both")
+);
+
+let
+  monorepoSrc' = monorepoSrc;
+
+  metadata = rec {
+    inherit
+      (import ./common-let.nix {
+        inherit (args)
+          lib
+          gitRelease
+          officialRelease
+          version
+          ;
+      })
+      releaseInfo
+      ;
+    inherit (releaseInfo) release_version version;
+    inherit
+      (import ./common-let.nix {
+        inherit
+          lib
+          fetchgit
+          fetchurl
+          release_version
+          gitRelease
+          officialRelease
+          monorepoSrc'
+          version
+          ;
+      })
+      gcc_meta
+      monorepoSrc
+      ;
+    src = monorepoSrc;
+    versionDir =
+      (toString ../.) + "/${if (gitRelease != null) then "git" else lib.versions.major release_version}";
+    getVersionFile =
+      p:
+      builtins.path {
+        name = baseNameOf p;
+        path =
+          let
+            patches = args.patchesFn (import ./patches.nix);
+
+            constraints = patches."${p}" or null;
+            matchConstraint =
+              {
+                before ? null,
+                after ? null,
+                path,
+              }:
+              let
+                check = fn: value: if value == null then true else fn release_version value;
+                matchBefore = check lib.versionOlder before;
+                matchAfter = check lib.versionAtLeast after;
+              in
+              matchBefore && matchAfter;
+
+            patchDir =
+              toString
+                (
+                  if constraints == null then
+                    { path = metadata.versionDir; }
+                  else
+                    (lib.findFirst matchConstraint { path = metadata.versionDir; } constraints)
+                ).path;
+          in
+          "${patchDir}/${p}";
+      };
+  };
+in
+makeScopeWithSplicing' {
+  inherit otherSplices;
+  f =
+    gccPackages:
+    let
+      callPackage = gccPackages.newScope (args // metadata);
+    in
+    {
+      stdenv = overrideCC stdenv gccPackages.gcc;
+
+      gcc-unwrapped = callPackage ./gcc {
+        bintools = binutils;
+      };
+
+      libbacktrace = callPackage ./libbacktrace { };
+      libiberty = callPackage ./libiberty { };
+      libsanitizer = callPackage ./libsanitizer { };
+      libquadmath = callPackage ./libquadmath { };
+
+      gfortran-unwrapped = gccPackages.gcc-unwrapped.override {
+        stdenv = overrideCC stdenv buildGccPackages.gcc;
+        langFortran = true;
+      };
+
+      gfortran = wrapCCWith {
+        cc = gccPackages.gfortran-unwrapped;
+        libcxx = targetGccPackages.libstdcxx;
+        bintools = binutils;
+        extraPackages = [
+          targetGccPackages.libgcc
+        ];
+        nixSupport.cc-cflags = [
+          "-B${targetGccPackages.libgcc}/lib"
+          "-B${targetGccPackages.libssp}/lib"
+          "-B${targetGccPackages.libatomic}/lib"
+          "-B${targetGccPackages.libgfortran}/lib/"
+        ];
+      };
+
+      gfortranNoLibgfortran = wrapCCWith {
+        cc = gccPackages.gfortran-unwrapped;
+        libcxx = targetGccPackages.libstdcxx;
+        bintools = binutils;
+        extraPackages = [
+          targetGccPackages.libgcc
+        ];
+        nixSupport.cc-cflags = [
+          "-B${targetGccPackages.libgcc}/lib"
+          "-B${targetGccPackages.libssp}/lib"
+          "-B${targetGccPackages.libatomic}/lib"
+        ];
+      };
+
+      gcc = wrapCCWith {
+        cc = gccPackages.gcc-unwrapped;
+        libcxx = targetGccPackages.libstdcxx;
+        bintools = binutils;
+        extraPackages = [
+          targetGccPackages.libgcc
+        ];
+        nixSupport.cc-cflags = [
+          "-B${targetGccPackages.libgcc}/lib"
+          "-B${targetGccPackages.libssp}/lib"
+          "-B${targetGccPackages.libatomic}/lib"
+        ];
+      };
+
+      gccNoLibgcc = wrapCCWith {
+        cc = gccPackages.gcc-unwrapped;
+        libcxx = null;
+        bintools = binutilsNoLibc;
+        extraPackages = [ ];
+        nixSupport.cc-cflags = [
+          "-nostartfiles"
+        ];
+      };
+
+      libgcc = callPackage ./libgcc {
+        stdenv = overrideCC stdenv buildGccPackages.gccNoLibgcc;
+      };
+
+      gccWithLibc = wrapCCWith {
+        cc = gccPackages.gcc-unwrapped;
+        libcxx = null;
+        bintools = binutils;
+        extraPackages = [
+          targetGccPackages.libgcc
+        ];
+        nixSupport.cc-cflags = [
+          "-B${targetGccPackages.libgcc}/lib"
+        ];
+      };
+
+      libssp = callPackage ./libssp {
+        stdenv = overrideCC stdenv buildGccPackages.gccWithLibc;
+      };
+
+      gccWithLibssp = wrapCCWith {
+        cc = gccPackages.gcc-unwrapped;
+        libcxx = null;
+        bintools = binutils;
+        extraPackages = [
+          targetGccPackages.libgcc
+        ];
+        nixSupport.cc-cflags = [
+          "-B${targetGccPackages.libgcc}/lib"
+          "-B${targetGccPackages.libssp}/lib"
+        ];
+      };
+
+      libatomic = callPackage ./libatomic {
+        stdenv = overrideCC stdenv buildGccPackages.gccWithLibssp;
+      };
+
+      gccWithLibatomic = wrapCCWith {
+        cc = gccPackages.gcc-unwrapped;
+        libcxx = null;
+        bintools = binutils;
+        extraPackages = [
+          targetGccPackages.libgcc
+        ];
+        nixSupport.cc-cflags = [
+          "-B${targetGccPackages.libgcc}/lib"
+          "-B${targetGccPackages.libssp}/lib"
+          "-B${targetGccPackages.libatomic}/lib"
+        ];
+      };
+
+      libgfortran = callPackage ./libgfortran {
+        stdenv = overrideCC stdenv buildGccPackages.gcc;
+        gfortran = buildGccPackages.gfortranNoLibgfortran;
+      };
+
+      libstdcxx = callPackage ./libstdcxx {
+        stdenv = overrideCC stdenv buildGccPackages.gccWithLibatomic;
+      };
+    };
+}

pkgs/development/compilers/gcc/ng/common/gcc/default.nix

@@ -0,0 +1,256 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  monorepoSrc ? null,
+  fetchpatch,
+  langAda ? false,
+  langC ? true,
+  langCC ? true,
+  langFortran ? false,
+  langGo ? false,
+  langJava ? false,
+  langObjC ? stdenv.targetPlatform.isDarwin,
+  langObjCpp ? stdenv.targetPlatform.isDarwin,
+  langJit ? false,
+  enablePlugin ? lib.systems.equals stdenv.hostPlatform stdenv.buildPlatform,
+  runCommand,
+  buildPackages,
+  isl,
+  zlib,
+  gmp,
+  libmpc,
+  mpfr,
+  perl,
+  texinfo,
+  which,
+  gettext,
+  getVersionFile,
+  buildGccPackages,
+  targetPackages,
+  libc,
+  bintools,
+}:
+let
+  inherit (stdenv) targetPlatform hostPlatform;
+  targetPrefix = lib.optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-";
+in
+stdenv.mkDerivation (finalAttrs: {
+  pname = "${targetPrefix}${if langFortran then "gfortran" else "gcc"}";
+  inherit version;
+
+  src = monorepoSrc;
+
+  outputs = [
+    "out"
+    "man"
+    "info"
+  ];
+
+  patches = [
+    (fetchpatch {
+      name = "for_each_path-functional-programming.patch";
+      url = "https://github.com/gcc-mirror/gcc/commit/f23bac62f46fc296a4d0526ef54824d406c3756c.diff";
+      hash = "sha256-J7SrypmVSbvYUzxWWvK2EwEbRsfGGLg4vNZuLEe6Xe0=";
+    })
+    (fetchpatch {
+      name = "find_a_program-separate-from-find_a_file.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250822234120.1988059-1-git@JohnEricson.me/raw";
+      hash = "sha256-0gaWaeFZq+a8q7Bcr3eILNjHh1LfzL/Lz4F+W+H6XIU=";
+    })
+    (fetchpatch {
+      name = "simplify-find_a_program-and-find_a_file.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250822234120.1988059-2-git@JohnEricson.me/raw";
+      hash = "sha256-ojdyszxLGL+njHK4eAaeBkxAhFTDI57j6lGuAf0A+N0=";
+    })
+    (fetchpatch {
+      name = "for_each_path-pass-machine-specific.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250822234120.1988059-3-git@JohnEricson.me/raw";
+      hash = "sha256-C5jUSyNchmZcE8RTXc2dHfCqNKuBHeiouLruK9UooSM=";
+    })
+    (fetchpatch {
+      name = "find_a_program-search-with-machine-prefix.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250822234120.1988059-4-git@JohnEricson.me/raw";
+      hash = "sha256-MwcO4OXPlcdaSYivsh5ru+Cfq6qybeAtgCgTEPGYg40=";
+    })
+
+    (getVersionFile "gcc/fix-collect2-paths.diff")
+  ];
+
+  enableParallelBuilding = true;
+
+  hardeningDisable = [
+    "format" # Some macro-indirect formatting in e.g. libcpp
+  ];
+
+  strictDeps = true;
+
+  depsBuildBuild = [ buildPackages.stdenv.cc ];
+  nativeBuildInputs = [
+    texinfo
+    which
+    gettext
+  ]
+  ++ lib.optional (perl != null) perl;
+
+  buildInputs = [
+    gmp
+    libmpc
+    mpfr
+  ]
+  ++ lib.optional (isl != null) isl
+  ++ lib.optional (zlib != null) zlib;
+
+  postUnpack = ''
+    mkdir -p ./build
+    buildRoot=$(readlink -e "./build")
+  '';
+
+  postPatch = ''
+    configureScripts=$(find . -name configure)
+    for configureScript in $configureScripts; do
+      patchShebangs $configureScript
+    done
+
+    patchShebangs libbacktrace/install-debuginfo-for-buildid.sh
+    patchShebangs runtest
+  ''
+  # This should kill all the stdinc frameworks that gcc and friends like to
+  # insert into default search paths.
+  + lib.optionalString hostPlatform.isDarwin ''
+    substituteInPlace gcc/config/darwin-c.c \
+      --replace 'if (stdinc)' 'if (0)'
+  '';
+
+  preConfigure =
+    # Don't built target libraries, because we want to build separately
+    ''
+      substituteInPlace configure \
+        --replace 'noconfigdirs=""' 'noconfigdirs="$noconfigdirs $target_libraries"'
+    ''
+    # HACK: if host and target config are the same, but the platforms are
+    # actually different we need to convince the configure script that it
+    # is in fact building a cross compiler although it doesn't believe it.
+    +
+      lib.optionalString (targetPlatform.config == hostPlatform.config && targetPlatform != hostPlatform)
+        ''
+          substituteInPlace configure --replace is_cross_compiler=no is_cross_compiler=yes
+        ''
+    # Cannot configure from src dir
+    + ''
+      cd "$buildRoot"
+
+      mkdir -p "$buildRoot/libbacktrace/.libs"
+      cp ${buildGccPackages.libbacktrace}/lib/libbacktrace.a "$buildRoot/libbacktrace/.libs/libbacktrace.a"
+      cp -r ${buildGccPackages.libbacktrace}/lib/*.la "$buildRoot/libbacktrace"
+      cp -r ${buildGccPackages.libbacktrace.dev}/include/*.h "$buildRoot/libbacktrace"
+
+      mkdir -p "$buildRoot/libiberty/pic"
+      cp ${buildGccPackages.libiberty}/lib/libiberty.a "$buildRoot/libiberty"
+      cp ${buildGccPackages.libiberty}/lib/libiberty_pic.a "$buildRoot/libiberty/pic/libiberty.a"
+      touch "$buildRoot/libiberty/stamp-noasandir"
+      touch "$buildRoot/libiberty/stamp-h"
+      touch "$buildRoot/libiberty/stamp-picdir"
+
+      mkdir -p "$buildRoot/build-${stdenv.hostPlatform.config}"
+      cp -r "$buildRoot/libiberty" "$buildRoot/build-${stdenv.hostPlatform.config}/libiberty"
+
+      configureScript=../$sourceRoot/configure
+    '';
+
+  # Don't store the configure flags in the resulting executables.
+  postConfigure = ''
+    sed -e '/TOPLEVEL_CONFIGURE_ARGUMENTS=/d' -i Makefile
+  '';
+
+  dontDisableStatic = true;
+
+  configurePlatforms = [
+    "build"
+    "host"
+    "target"
+  ];
+
+  configureFlags = [
+    # Force target prefix. The behavior if `--target` and `--host` are
+    # specified is inconsistent: Sometimes specifying `--target` always causes
+    # a prefix to be generated, sometimes it's only added if the `--host` and
+    # `--target` differ. This means that sometimes there may be a prefix even
+    # though nixpkgs doesn't expect one and sometimes there may be none even
+    # though nixpkgs expects one (since not all information is serialized into
+    # the config attribute). The easiest way out of these problems is to always
+    # set the program prefix, so gcc will conform to our expectations.
+    "--program-prefix=${targetPrefix}"
+
+    "--disable-dependency-tracking"
+    "--enable-fast-install"
+    "--disable-serial-configure"
+    "--disable-bootstrap"
+    "--disable-decimal-float"
+    "--disable-install-libiberty"
+    "--disable-multilib"
+    "--disable-nls"
+    "--disable-shared"
+    "--enable-default-pie"
+    "--enable-languages=${
+      lib.concatStrings (
+        lib.intersperse "," (
+          lib.optional langC "c"
+          ++ lib.optional langCC "c++"
+          ++ lib.optional langFortran "fortran"
+          ++ lib.optional langJava "java"
+          ++ lib.optional langAda "ada"
+          ++ lib.optional langGo "go"
+          ++ lib.optional langObjC "objc"
+          ++ lib.optional langObjCpp "obj-c++"
+          ++ lib.optional langJit "jit"
+        )
+      )
+    }"
+    (lib.withFeature (isl != null) "isl")
+    "--without-headers"
+    "--with-gnu-as"
+    "--with-gnu-ld"
+    "--with-as=${lib.getExe' bintools "${bintools.targetPrefix}as"}"
+    "--with-system-zlib"
+    "--without-included-gettext"
+    "--enable-linker-build-id"
+    "--with-sysroot=${lib.getDev (targetPackages.libc or libc)}"
+    "--with-native-system-header-dir=/include"
+  ]
+  ++ lib.optionals enablePlugin [
+    "--enable-plugin"
+    "--enable-plugins"
+  ]
+  ++
+    # Only pass when the arch supports it.
+    # Exclude RISC-V because GCC likes to fail when the string is empty on RISC-V.
+    lib.optionals (targetPlatform.isAarch || targetPlatform.isAvr || targetPlatform.isx86_64) [
+      "--with-multilib-list="
+    ];
+
+  doCheck = false;
+
+  postInstall = ''
+    moveToOutput "lib/gcc/${targetPlatform.config}/${version}/plugin/include" "''${!outputDev}"
+  '';
+
+  passthru = {
+    inherit
+      langC
+      langCC
+      langObjC
+      langObjCpp
+      langAda
+      langFortran
+      langGo
+      ;
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libatomic/default.nix

@@ -0,0 +1,94 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  getVersionFile,
+  monorepoSrc ? null,
+  fetchpatch,
+  autoreconfHook269,
+  runCommand,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libatomic";
+  inherit version;
+
+  src = runCommand "libatomic-src-${version}" { src = monorepoSrc; } ''
+    runPhase unpackPhase
+
+    mkdir -p "$out/gcc"
+    cp gcc/BASE-VER "$out/gcc"
+    cp gcc/DATESTAMP "$out/gcc"
+
+    cp -r libatomic "$out"
+
+    cp -r config "$out"
+    cp -r multilib.am "$out"
+    cp -r libtool.m4 "$out"
+
+    cp config.guess "$out"
+    cp config.rpath "$out"
+    cp config.sub "$out"
+    cp config-ml.in "$out"
+    cp ltmain.sh "$out"
+    cp install-sh "$out"
+    cp mkinstalldirs "$out"
+
+    [[ -f MD5SUMS ]]; cp MD5SUMS "$out"
+  '';
+
+  patches = [
+    (fetchpatch {
+      name = "custom-threading-model.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250716204545.1063669-1-git@JohnEricson.me/raw";
+      hash = "sha256-kxNntY2r4i/+XHQSpf9bYV2Jg+FD/pD5TiMn5hd4ckk=";
+      includes = [
+        "config/*"
+        "libatomic/*"
+      ];
+    })
+  ];
+
+  postUnpack = ''
+    mkdir -p ./build
+    buildRoot=$(readlink -e "./build")
+  '';
+
+  preAutoreconf = ''
+    sourceRoot=$(readlink -e "./libatomic")
+    cd $sourceRoot
+  '';
+
+  enableParallelBuilding = true;
+
+  nativeBuildInputs = [
+    autoreconfHook269
+  ];
+
+  configurePlatforms = [
+    "build"
+    "host"
+  ];
+
+  configureFlags = [
+    "--disable-dependency-tracking"
+    "cross_compiling=true"
+    "--disable-multilib"
+  ];
+
+  preConfigure = ''
+    cd "$buildRoot"
+    configureScript=$sourceRoot/configure
+  '';
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libbacktrace/default.nix

@@ -0,0 +1,74 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  monorepoSrc ? null,
+  runCommand,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libbacktrace";
+  inherit version;
+
+  src = runCommand "libbacktrace-src-${version}" { src = monorepoSrc; } ''
+    runPhase unpackPhase
+
+    mkdir -p "$out/gcc"
+    cp gcc/BASE-VER "$out/gcc"
+    cp gcc/DATESTAMP "$out/gcc"
+
+    cp -r include "$out"
+    cp -r libbacktrace "$out"
+
+    cp config.guess "$out"
+    cp config.rpath "$out"
+    cp config.sub "$out"
+    cp config-ml.in "$out"
+    cp ltmain.sh "$out"
+    cp install-sh "$out"
+    cp move-if-change "$out"
+    cp mkinstalldirs "$out"
+    cp test-driver "$out"
+
+    [[ -f MD5SUMS ]]; cp MD5SUMS "$out"
+  '';
+
+  outputs = [
+    "out"
+    "dev"
+  ];
+
+  enableParallelBuilding = true;
+
+  sourceRoot = "${finalAttrs.src.name}/libbacktrace";
+
+  preConfigure = ''
+    mkdir ../../build
+    cd ../../build
+    configureScript=../$sourceRoot/configure
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p "$out/lib"
+    cp .libs/*.a "$out/lib"
+    cp libbacktrace*.la "$out/lib"
+
+    mkdir -p "$dev/include"
+    cp backtrace-supported.h "$dev/include"
+
+    runHook postInstall
+  '';
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libgcc/default.nix

@@ -0,0 +1,224 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  getVersionFile,
+  monorepoSrc ? null,
+  fetchpatch,
+  autoreconfHook269,
+  buildGccPackages,
+  buildPackages,
+  which,
+  python3,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libgcc";
+  inherit version;
+
+  src = monorepoSrc;
+
+  outputs = [
+    "out"
+    "dev"
+  ];
+
+  strictDeps = true;
+
+  depsBuildBuild = [
+    buildPackages.stdenv.cc
+    buildGccPackages.libiberty
+  ];
+
+  nativeBuildInputs = [
+    autoreconfHook269
+    which
+    python3
+  ];
+
+  patches = [
+    (fetchpatch {
+      name = "delete-MACHMODE_H.patch";
+      url = "https://github.com/gcc-mirror/gcc/commit/493aae4b034d62054d5e7e54dc06cd9a8be54e29.diff";
+      hash = "sha256-oEk0lnI96RlpALWpb7J+GnrtgQsFVqDO57I/zjiqqTk=";
+    })
+    (fetchpatch {
+      name = "custom-threading-model.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250716204545.1063669-1-git@JohnEricson.me/raw";
+      hash = "sha256-NgiC4cFeFInXXg27me1XpSeImPaL0WHs50Tf1YHz4ps=";
+    })
+    (fetchpatch {
+      name = "libgcc.mvars-less-0.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250716234028.1153560-1-John.Ericson@Obsidian.Systems/raw";
+      hash = "sha256-NEcieDCsy+7IRU3qQKVD3i57OuwGZKB/rmNF8X2I1n0=";
+    })
+    (fetchpatch {
+      name = "libgcc.mvars-less-1.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250716234028.1153560-2-John.Ericson@Obsidian.Systems/raw";
+      hash = "sha256-nfRC4f6m3kHDro4+6E4y1ZPs+prxBQmn0H2rzIjaMWM=";
+    })
+    (fetchpatch {
+      name = "regular-libdir-includedir.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250717174911.1536129-1-git@JohnEricson.me/raw";
+      hash = "sha256-Cn7rvg1FI7H/26GzSe4pv5VW/gvwbwGqivAqEeawkwk=";
+    })
+    (getVersionFile "libgcc/force-regular-dirs.patch")
+  ];
+
+  autoreconfFlags = "--install --force --verbose . libgcc";
+
+  postUnpack = ''
+    mkdir -p ./build
+    buildRoot=$(readlink -e "./build")
+  '';
+
+  postPatch = ''
+    sourceRoot=$(readlink -e "./libgcc")
+  '';
+
+  enableParallelBuilding = true;
+
+  preConfigure = ''
+    cd "$buildRoot"
+
+    mkdir -p build-${stdenv.buildPlatform.config}/libiberty/
+    cd build-${stdenv.buildPlatform.config}/libiberty/
+    ln -s ${buildGccPackages.libiberty}/lib/libiberty.a ./
+
+    mkdir -p "$buildRoot/gcc"
+    cd "$buildRoot/gcc"
+
+    (
+    export AS_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $AS_FOR_BUILD)"}
+    export CC_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $CC_FOR_BUILD)"}
+    export CPP_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $CPP_FOR_BUILD)"}
+    export CXX_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $CXX_FOR_BUILD)"}
+    export LD_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc.bintools "$(basename $LD_FOR_BUILD)"}
+
+    export AS=$AS_FOR_BUILD
+    export CC=$CC_FOR_BUILD
+    export CPP=$CPP_FOR_BUILD
+    export CXX=$CXX_FOR_BUILD
+    export LD=$LD_FOR_BUILD
+
+    export AS_FOR_TARGET=${lib.getExe' stdenv.cc "$(basename $AS)"}
+    export CC_FOR_TARGET=${lib.getExe' stdenv.cc "$(basename $CC)"}
+    export CPP_FOR_TARGET=${lib.getExe' stdenv.cc "$(basename $CPP)"}
+    export LD_FOR_TARGET=${lib.getExe' stdenv.cc.bintools "$(basename $LD)"}
+
+    export NIX_CFLAGS_COMPILE_FOR_BUILD+=' -DGENERATOR_FILE=1'
+
+    "$sourceRoot/../gcc/configure" $topLevelConfigureFlags
+
+    sed -e 's,libgcc.mvars:.*$,libgcc.mvars:,' -i Makefile
+
+    make \
+      config.h \
+      libgcc.mvars \
+      tconfig.h \
+      tm.h \
+      options.h \
+      insn-constants.h \
+      version.h
+    )
+    mkdir -p "$buildRoot/gcc/include"
+
+    mkdir -p "$buildRoot/gcc/${stdenv.hostPlatform.config}/libgcc"
+    cd "$buildRoot/gcc/${stdenv.hostPlatform.config}/libgcc"
+    configureScript=$sourceRoot/configure
+    chmod +x "$configureScript"
+
+    export AS_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $AS_FOR_BUILD)"}
+    export CC_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $CC_FOR_BUILD)"}
+    export CPP_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $CPP_FOR_BUILD)"}
+    export CXX_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$(basename $CXX_FOR_BUILD)"}
+    export LD_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc.bintools "$(basename $LD_FOR_BUILD)"}
+
+    export AS=${lib.getExe' stdenv.cc "$(basename $AS)"}
+    export CC=${lib.getExe' stdenv.cc "$(basename $CC)"}
+    export CPP=${lib.getExe' stdenv.cc "$(basename $CPP)"}
+    export CXX=${lib.getExe' stdenv.cc "$(basename $CXX)"}
+    export LD=${lib.getExe' stdenv.cc.bintools "$(basename $LD)"}
+
+    export AS_FOR_TARGET=${lib.getExe' stdenv.cc "$(basename $AS_FOR_TARGET)"}
+    export CC_FOR_TARGET=${lib.getExe' stdenv.cc "$(basename $CC_FOR_TARGET)"}
+    export CPP_FOR_TARGET=${lib.getExe' stdenv.cc "$(basename $CPP_FOR_TARGET)"}
+    export LD_FOR_TARGET=${lib.getExe' stdenv.cc.bintools "$(basename $LD_FOR_TARGET)"}
+  ''
+  + lib.optionalString stdenv.hostPlatform.isMusl ''
+    NIX_CFLAGS_COMPILE_OLD=$NIX_CFLAGS_COMPILE
+    NIX_CFLAGS_COMPILE+=' -isystem ${stdenv.cc.cc}/lib/gcc/${stdenv.hostPlatform.config}/${version}/include-fixed'
+  '';
+
+  topLevelConfigureFlags = [
+    "--build=${stdenv.buildPlatform.config}"
+    "--host=${stdenv.buildPlatform.config}"
+    "--target=${stdenv.hostPlatform.config}"
+
+    "--disable-bootstrap"
+    "--disable-multilib"
+    "--enable-languages=c"
+
+    "--disable-fixincludes"
+    "--disable-intl"
+    "--disable-lto"
+    "--disable-libatomic"
+    "--disable-libbacktrace"
+    "--disable-libcpp"
+    "--disable-libssp"
+    "--disable-libquadmath"
+    "--disable-libgomp"
+    "--disable-libvtv"
+    "--disable-vtable-verify"
+
+    "--with-system-zlib"
+  ]
+  ++
+    lib.optional (!stdenv.hostPlatform.isRiscV)
+      # RISC-V does not like it being empty
+      "--with-multilib-list="
+  ++
+    lib.optional (stdenv.hostPlatform.libc == "glibc")
+      # Cheat and use previous stage's glibc to avoid infinite recursion. As
+      # of GCC 11, libgcc only cares if the version is greater than 2.19,
+      # which is quite ancient, so this little lie should be fine.
+      "--with-glibc-version=${buildPackages.glibc.version}";
+
+  configurePlatforms = [
+    "build"
+    "host"
+  ];
+
+  configureFlags = [
+    "--disable-dependency-tracking"
+    "gcc_cv_target_thread_file=single"
+    # $CC cannot link binaries, let alone run then
+    "cross_compiling=true"
+    # Do not have dynamic linker without libc
+    "--enable-static"
+    "--disable-shared"
+  ];
+
+  # Set the variable back the way it was, see corresponding code in
+  # `preConfigure`.
+  postConfigure = lib.optionalString stdenv.hostPlatform.isMusl ''
+    NIX_CFLAGS_COMPILE=$NIX_CFLAGS_COMPILE_OLD
+  '';
+
+  makeFlags = [ "MULTIBUILDTOP:=../" ];
+
+  postInstall = ''
+    install -c -m 644 gthr-default.h "$dev/include"
+  '';
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libgfortran/default.nix

@@ -0,0 +1,188 @@
+{
+  lib,
+  stdenv,
+  gfortran,
+  gcc_meta,
+  release_version,
+  version,
+  getVersionFile,
+  monorepoSrc ? null,
+  autoreconfHook269,
+  libiberty,
+  buildPackages,
+  libgcc,
+  libbacktrace,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libgfortran";
+  inherit version;
+
+  src = monorepoSrc;
+
+  outputs = [
+    "out"
+    "dev"
+  ];
+
+  strictDeps = true;
+
+  depsBuildBuild = [ buildPackages.stdenv.cc ];
+  nativeBuildInputs = [
+    autoreconfHook269
+    libiberty
+    gfortran
+  ];
+
+  patches = [
+    (getVersionFile "libgfortran/force-regular-dirs.patch")
+  ];
+
+  autoreconfFlags = "--install --force --verbose . libgfortran";
+
+  postUnpack = ''
+    mkdir -p ./build
+    buildRoot=$(readlink -e "./build")
+  '';
+
+  postPatch = ''
+    sourceRoot=$(readlink -e "./libgfortran")
+  '';
+
+  enableParallelBuilding = true;
+
+  preConfigure = ''
+    cd "$buildRoot"
+
+    mkdir -p build-${stdenv.buildPlatform.config}/libiberty/
+    cd build-${stdenv.buildPlatform.config}/libiberty/
+    ln -s ${libiberty}/lib/libiberty.a ./
+
+    mkdir -p "$buildRoot/gcc"
+    cd "$buildRoot/gcc"
+
+    (
+    export AS_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$AS_FOR_BUILD"}
+    export CC_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$CC_FOR_BUILD"}
+    export CPP_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$CPP_FOR_BUILD"}
+    export CXX_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$CXX_FOR_BUILD"}
+    export LD_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc.bintools "$LD_FOR_BUILD"}
+
+    export AS=$AS_FOR_BUILD
+    export CC=$CC_FOR_BUILD
+    export CPP=$CPP_FOR_BUILD
+    export CXX=$CXX_FOR_BUILD
+    export LD=$LD_FOR_BUILD
+
+    export AS_FOR_TARGET=${lib.getExe' stdenv.cc "$AS"}
+    export CC_FOR_TARGET=${lib.getExe' stdenv.cc "$CC"}
+    export CPP_FOR_TARGET=${lib.getExe' stdenv.cc "$CPP"}
+    export LD_FOR_TARGET=${lib.getExe' stdenv.cc.bintools "$LD"}
+
+    export NIX_CFLAGS_COMPILE_FOR_BUILD+=' -DGENERATOR_FILE=1'
+
+    "$sourceRoot/../gcc/configure" $topLevelConfigureFlags
+
+    make \
+      config.h
+    )
+    mkdir -p "$buildRoot/gcc/include"
+
+    mkdir -p "$buildRoot/gcc/libbacktrace/.libs"
+    cp ${libbacktrace}/lib/libbacktrace.a "$buildRoot/gcc/libbacktrace/.libs/libbacktrace.a"
+    cp -r ${libbacktrace}/lib/*.la "$buildRoot/gcc/libbacktrace"
+    cp -r ${libbacktrace.dev}/include/*.h "$buildRoot/gcc/libbacktrace"
+
+    mkdir -p "$buildRoot/gcc/libgcc"
+    ln -s "${libgcc.dev}/include/gthr-default.h" "$buildRoot/gcc/libgcc"
+
+    mkdir -p "$buildRoot/gcc/${stdenv.hostPlatform.config}/libgfortran"
+    ln -s "$buildRoot/gcc/libbacktrace" "$buildRoot/gcc/${stdenv.buildPlatform.config}/libbacktrace"
+    ln -s "$buildRoot/gcc/libgcc" "$buildRoot/gcc/${stdenv.buildPlatform.config}/libgcc"
+    cd "$buildRoot/gcc/${stdenv.hostPlatform.config}/libgfortran"
+    configureScript=$sourceRoot/configure
+    chmod +x "$configureScript"
+
+    export AS_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$AS_FOR_BUILD"}
+    export CC_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$CC_FOR_BUILD"}
+    export CPP_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$CPP_FOR_BUILD"}
+    export CXX_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc "$CXX_FOR_BUILD"}
+    export LD_FOR_BUILD=${lib.getExe' buildPackages.stdenv.cc.bintools "$LD_FOR_BUILD"}
+
+    export AS=${lib.getExe' stdenv.cc "$AS"}
+    export CC=${lib.getExe' stdenv.cc "$CC"}
+    export CPP=${lib.getExe' stdenv.cc "$CPP"}
+    export CXX=${lib.getExe' stdenv.cc "$CXX"}
+    export LD=${lib.getExe' stdenv.cc.bintools "$LD"}
+
+    export AS_FOR_TARGET=${lib.getExe' stdenv.cc "$AS_FOR_TARGET"}
+    export CC_FOR_TARGET=${lib.getExe' stdenv.cc "$CC_FOR_TARGET"}
+    export CPP_FOR_TARGET=${lib.getExe' stdenv.cc "$CPP_FOR_TARGET"}
+    export LD_FOR_TARGET=${lib.getExe' stdenv.cc.bintools "$LD_FOR_TARGET"}
+  ''
+  + lib.optionalString stdenv.hostPlatform.isMusl ''
+    NIX_CFLAGS_COMPILE_OLD=$NIX_CFLAGS_COMPILE
+    NIX_CFLAGS_COMPILE+=' -isystem ${stdenv.cc.cc}/lib/gcc/${stdenv.hostPlatform.config}/${version}/include-fixed'
+  '';
+
+  topLevelConfigureFlags = [
+    "--build=${stdenv.buildPlatform.config}"
+    "--host=${stdenv.buildPlatform.config}"
+    "--target=${stdenv.hostPlatform.config}"
+
+    "--disable-bootstrap"
+    "--disable-multilib"
+    "--with-multilib-list="
+    "--enable-languages=fortran"
+
+    "--disable-fixincludes"
+    "--disable-intl"
+    "--disable-lto"
+    "--disable-libatomic"
+    "--disable-libbacktrace"
+    "--disable-libcpp"
+    "--disable-libssp"
+    "--disable-libquadmath"
+    "--disable-libgomp"
+    "--disable-libvtv"
+    "--disable-vtable-verify"
+
+    "--with-system-zlib"
+  ]
+  ++
+    lib.optional (stdenv.hostPlatform.libc == "glibc")
+      # Cheat and use previous stage's glibc to avoid infinite recursion. As
+      # of GCC 11, libgcc only cares if the version is greater than 2.19,
+      # which is quite ancient, so this little lie should be fine.
+      "--with-glibc-version=${buildPackages.glibc.version}";
+
+  configurePlatforms = [
+    "build"
+    "host"
+  ];
+
+  configureFlags = [
+    "--disable-dependency-tracking"
+    "gcc_cv_target_thread_file=single"
+    # $CC cannot link binaries, let alone run then
+    "cross_compiling=true"
+    "--with-toolexeclibdir=${placeholder "dev"}/lib"
+  ];
+
+  # Set the variable back the way it was, see corresponding code in
+  # `preConfigure`.
+  postConfigure = lib.optionalString stdenv.hostPlatform.isMusl ''
+    NIX_CFLAGS_COMPILE=$NIX_CFLAGS_COMPILE_OLD
+  '';
+
+  makeFlags = [ "MULTIBUILDTOP:=../" ];
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libiberty/default.nix

@@ -0,0 +1,68 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  monorepoSrc ? null,
+  runCommand,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libiberty";
+  inherit version;
+
+  src = runCommand "libiberty-src-${version}" { src = monorepoSrc; } ''
+    runPhase unpackPhase
+
+    mkdir -p "$out/gcc"
+    cp gcc/BASE-VER "$out/gcc"
+    cp gcc/DATESTAMP "$out/gcc"
+
+    cp -r include "$out"
+    cp -r libiberty "$out"
+
+    cp config.guess "$out"
+    cp config.rpath "$out"
+    cp config.sub "$out"
+    cp config-ml.in "$out"
+    cp ltmain.sh "$out"
+    cp install-sh "$out"
+    cp mkinstalldirs "$out"
+
+    [[ -f MD5SUMS ]]; cp MD5SUMS "$out"
+  '';
+
+  outputs = [
+    "out"
+    "dev"
+  ];
+
+  enableParallelBuilding = true;
+
+  sourceRoot = "${finalAttrs.src.name}/libiberty";
+
+  preConfigure = ''
+    mkdir ../../build
+    cd ../../build
+    configureScript=../$sourceRoot/configure
+  '';
+
+  configureFlags = [
+    "--enable-install-libiberty"
+  ]
+  ++ lib.optional (!stdenv.hostPlatform.isStatic) "--enable-shared";
+
+  postInstall = ''
+    cp pic/libiberty.a $out/lib/libiberty_pic.a
+  '';
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libquadmath/default.nix

@@ -0,0 +1,51 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  monorepoSrc ? null,
+  runCommand,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libquadmath";
+  inherit version;
+
+  src = runCommand "libquadmath-src-${version}" { src = monorepoSrc; } ''
+    runPhase unpackPhase
+
+    mkdir -p "$out/gcc"
+    cp gcc/BASE-VER "$out/gcc"
+    cp gcc/DATESTAMP "$out/gcc"
+
+    cp -r libquadmath "$out"
+
+    cp config.guess "$out"
+    cp config.rpath "$out"
+    cp config.sub "$out"
+    cp config-ml.in "$out"
+    cp ltmain.sh "$out"
+    cp install-sh "$out"
+    cp mkinstalldirs "$out"
+
+    [[ -f MD5SUMS ]]; cp MD5SUMS "$out"
+  '';
+
+  sourceRoot = "${finalAttrs.src.name}/libquadmath";
+
+  preConfigure = ''
+    mkdir ../../build
+    cd ../../build
+    configureScript=../$sourceRoot/configure
+  '';
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libsanitizer/default.nix

@@ -0,0 +1,57 @@
+{
+  lib,
+  stdenv,
+  libstdcxx,
+  gcc_meta,
+  release_version,
+  version,
+  monorepoSrc ? null,
+  runCommand,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libsanitizer";
+  inherit version;
+
+  src = runCommand "libsanitizer-src-${version}" { src = monorepoSrc; } ''
+    runPhase unpackPhase
+
+    mkdir -p "$out/gcc"
+    cp gcc/BASE-VER "$out/gcc"
+    cp gcc/DATESTAMP "$out/gcc"
+
+    cp -r libsanitizer "$out"
+
+    cp config.guess "$out"
+    cp config.rpath "$out"
+    cp config.sub "$out"
+    cp config-ml.in "$out"
+    cp ltmain.sh "$out"
+    cp install-sh "$out"
+    cp mkinstalldirs "$out"
+
+    [[ -f MD5SUMS ]]; cp MD5SUMS "$out"
+  '';
+
+  sourceRoot = "${finalAttrs.src.name}/libsanitizer";
+
+  postUnpack = ''
+    mkdir -p libstdc++-v3/src/
+    ln -s ${libstdcxx}/lib/libstdc++.la libstdc++-v3/src/libstdc++.la
+  '';
+
+  preConfigure = ''
+    mkdir ../../build
+    cd ../../build
+    configureScript=../$sourceRoot/configure
+  '';
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libssp/default.nix

@@ -0,0 +1,101 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  getVersionFile,
+  monorepoSrc ? null,
+  fetchpatch,
+  autoreconfHook269,
+  runCommand,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libssp";
+  inherit version;
+
+  src = runCommand "libssp-src-${version}" { src = monorepoSrc; } ''
+    runPhase unpackPhase
+
+    mkdir -p "$out/gcc"
+    cp gcc/BASE-VER "$out/gcc"
+    cp gcc/DATESTAMP "$out/gcc"
+
+    cp -r libssp "$out"
+
+    cp -r config "$out"
+    cp -r multilib.am "$out"
+
+    cp config.guess "$out"
+    cp config.rpath "$out"
+    cp config.sub "$out"
+    cp config-ml.in "$out"
+    cp ltmain.sh "$out"
+    cp install-sh "$out"
+    cp mkinstalldirs "$out"
+
+    [[ -f MD5SUMS ]]; cp MD5SUMS "$out"
+  '';
+
+  outputs = [
+    "out"
+    "dev"
+  ];
+
+  patches = [
+    (fetchpatch {
+      name = "regular-libdir-includedir.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250720172933.2404828-1-git@JohnEricson.me/raw";
+      hash = "sha256-W7dcy1Tm3O2reK7kx83DRv8W97qUfaqDbKLiLXIegRw=";
+    })
+    (getVersionFile "libssp/force-regular-dirs.patch")
+  ];
+
+  postUnpack = ''
+    mkdir -p ./build
+    buildRoot=$(readlink -e "./build")
+  '';
+
+  preAutoreconf = ''
+    sourceRoot=$(readlink -e "./libssp")
+    cd $sourceRoot
+  '';
+
+  enableParallelBuilding = true;
+
+  nativeBuildInputs = [
+    autoreconfHook269
+  ];
+
+  configurePlatforms = [
+    "build"
+    "host"
+  ];
+
+  configureFlags = [
+    "--disable-dependency-tracking"
+    "cross_compiling=true"
+    "--disable-multilib"
+  ];
+
+  preConfigure = ''
+    cd "$buildRoot"
+    configureScript=$sourceRoot/configure
+  '';
+
+  hardeningDisable = [
+    "fortify"
+    # Because we are building it!
+    "stackprotector"
+  ];
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/";
+  };
+})

pkgs/development/compilers/gcc/ng/common/libstdcxx/default.nix

@@ -0,0 +1,127 @@
+{
+  lib,
+  stdenv,
+  gcc_meta,
+  release_version,
+  version,
+  getVersionFile,
+  monorepoSrc ? null,
+  fetchpatch,
+  autoreconfHook269,
+  runCommand,
+  gettext,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libstdcxx";
+  inherit version;
+
+  src = runCommand "libstdcxx-src-${version}" { src = monorepoSrc; } ''
+    runPhase unpackPhase
+
+    mkdir -p "$out/gcc"
+    cp gcc/BASE-VER "$out/gcc"
+    cp gcc/DATESTAMP "$out/gcc"
+
+    mkdir -p "$out/libgcc"
+    cp libgcc/gthr*.h "$out/libgcc"
+    cp libgcc/unwind-pe.h "$out/libgcc"
+
+    cp -r libstdc++-v3 "$out"
+
+    cp -r libiberty "$out"
+    cp -r include "$out"
+    cp -r contrib "$out"
+
+    cp -r config "$out"
+    cp -r multilib.am "$out"
+
+    cp config.guess "$out"
+    cp config.rpath "$out"
+    cp config.sub "$out"
+    cp config-ml.in "$out"
+    cp ltmain.sh "$out"
+    cp install-sh "$out"
+    cp mkinstalldirs "$out"
+
+    [[ -f MD5SUMS ]]; cp MD5SUMS "$out"
+  '';
+
+  outputs = [
+    "out"
+    "dev"
+  ];
+
+  patches = [
+    (fetchpatch {
+      name = "custom-threading-model.patch";
+      url = "https://inbox.sourceware.org/gcc-patches/20250716204545.1063669-1-git@JohnEricson.me/raw";
+      hash = "sha256-jPP0+MoPLtCwWcW6doO6KHCppwAYK40qNVyriLXcGOg=";
+      includes = [
+        "config/*"
+        "libstdc++-v3/*"
+      ];
+    })
+    (getVersionFile "libstdcxx/force-regular-dirs.patch")
+  ];
+
+  postUnpack = ''
+    mkdir -p ./build
+    buildRoot=$(readlink -e "./build")
+  '';
+
+  preAutoreconf = ''
+    sourceRoot=$(readlink -e "./libstdc++-v3")
+    cd $sourceRoot
+  '';
+
+  enableParallelBuilding = true;
+
+  nativeBuildInputs = [
+    autoreconfHook269
+    gettext
+  ];
+
+  preConfigure = ''
+    cd "$buildRoot"
+    configureScript=$sourceRoot/configure
+    chmod +x "$configureScript"
+  '';
+
+  configurePlatforms = [
+    "build"
+    "host"
+  ];
+
+  configureFlags = [
+    "--disable-dependency-tracking"
+    "gcc_cv_target_thread_file=posix"
+    "cross_compiling=true"
+    "--disable-multilib"
+
+    "--enable-clocale=gnu"
+    "--disable-libstdcxx-pch"
+    "--disable-vtable-verify"
+    "--enable-libstdcxx-visibility"
+    "--with-default-libstdcxx-abi=new"
+  ];
+
+  hardeningDisable = [
+    # PATH_MAX
+    "fortify"
+  ];
+
+  postInstall = ''
+    moveToOutput lib/libstdc++.modules.json "$dev"
+  '';
+
+  doCheck = true;
+
+  passthru = {
+    isGNU = true;
+  };
+
+  meta = gcc_meta // {
+    homepage = "https://gcc.gnu.org/onlinedocs/libstdc++";
+    description = "GNU C++ Library";
+  };
+})

pkgs/development/compilers/gcc/ng/common/patches.nix

@@ -0,0 +1,38 @@
+{
+  # TODO: fix up and send to upstream
+  "gcc/fix-collect2-paths.diff" = [
+    {
+      after = "15";
+      path = ../15;
+    }
+  ];
+
+  # In Git: https://github.com/Ericson2314/gcc/tree/regular-dirs-in-libgcc-15
+  "libgcc/force-regular-dirs.patch" = [
+    {
+      after = "15";
+      path = ../15;
+    }
+  ];
+  # In Git: https://github.com/Ericson2314/gcc/tree/regular-dirs-in-libssp-15
+  "libssp/force-regular-dirs.patch" = [
+    {
+      after = "15";
+      path = ../15;
+    }
+  ];
+  # In Git: https://github.com/Ericson2314/gcc/tree/libstdcxx-force-regular-dirs-15
+  "libstdcxx/force-regular-dirs.patch" = [
+    {
+      after = "15";
+      path = ../15;
+    }
+  ];
+  # In Git: https://github.com/Ericson2314/gcc/tree/libgfortran-force-regular-dirs-15
+  "libgfortran/force-regular-dirs.patch" = [
+    {
+      after = "15";
+      path = ../15;
+    }
+  ];
+}

pkgs/development/compilers/gcc/ng/default.nix

@@ -0,0 +1,70 @@
+{
+  lib,
+  callPackage,
+  stdenv,
+  stdenvAdapters,
+  recurseIntoAttrs,
+  gccVersions ? { },
+  patchesFn ? lib.id,
+  buildPackages,
+  targetPackages,
+  binutilsNoLibc,
+  binutils,
+  generateSplicesForMkScope,
+  ...
+}@packageSetArgs:
+let
+  versions = {
+    "15.1.0".officialRelease.sha256 = "sha256-4rCewhZg8B/s/7cV4BICZSFpQ/A40OSKmGhxPlTwbOo=";
+  }
+  // gccVersions;
+
+  mkPackage =
+    {
+      name ? null,
+      officialRelease ? null,
+      gitRelease ? null,
+      monorepoSrc ? null,
+      version ? null,
+    }@args:
+    let
+      inherit
+        (import ./common/common-let.nix {
+          inherit
+            lib
+            gitRelease
+            officialRelease
+            version
+            ;
+        })
+        releaseInfo
+        ;
+      inherit (releaseInfo) release_version;
+      attrName =
+        args.name or (if (gitRelease != null) then "git" else lib.versions.major release_version);
+    in
+    lib.nameValuePair attrName (
+      recurseIntoAttrs (
+        callPackage ./common (
+          {
+            inherit (stdenvAdapters) overrideCC;
+            inherit
+              officialRelease
+              gitRelease
+              monorepoSrc
+              version
+              patchesFn
+              ;
+
+            buildGccPackages = buildPackages."gccNGPackages_${attrName}";
+            targetGccPackages = targetPackages."gccNGPackages_${attrName}" or gccPackages."${attrName}";
+            otherSplices = generateSplicesForMkScope "gccNGPackages_${attrName}";
+          }
+          // packageSetArgs # Allow overrides.
+        )
+      )
+    );
+
+  gccPackages = lib.mapAttrs' (version: args: mkPackage (args // { inherit version; })) versions;
+in
+gccPackages // { inherit mkPackage; }