Remove mingw-std-threads from 3rd party deps and use native libs/headers instead (#7283)

* Remove mingw-std-threads from 3rd party deps

 and use native libs/headers instead

* switch MinGW to POSIX in CI

src/3rdparty/CMakeLists.txt

@@ -11,12 +11,6 @@ target_include_directories(jack_headers INTERFACE jack2/common)
 ADD_SUBDIRECTORY(hiir)
 ADD_SUBDIRECTORY(weakjack)
 
-if(MINGW)
-	option(MINGW_STDTHREADS_GENERATE_STDHEADERS "" ON)
-	add_subdirectory(mingw-std-threads)
-	set(LMMS_USE_MINGW_STD_THREADS ON PARENT_SCOPE)
-endif()
-
 # The lockless ring buffer library is linked as part of the core
 add_library(ringbuffer OBJECT
 	ringbuffer/src/lib/ringbuffer.cpp

src/CMakeLists.txt

@@ -154,10 +154,6 @@ if(LMMS_HAVE_OGGVORBIS)
 	list(APPEND EXTRA_LIBRARIES Vorbis::vorbisenc Vorbis::vorbisfile)
 endif()
 
-if(LMMS_USE_MINGW_STD_THREADS)
-	list(APPEND EXTRA_LIBRARIES mingw_stdthreads)
-endif()
-
 SET(LMMS_REQUIRED_LIBS ${LMMS_REQUIRED_LIBS}
 	${CMAKE_THREAD_LIBS_INIT}
 	${QT_LIBRARIES}

src/core/FileSearch.cpp

@@ -28,11 +28,7 @@
 #include <chrono>
 #include <lmmsconfig.h>
 
-#ifdef __MINGW32__
-#include <mingw.thread.h>
-#else
 #include <thread>
-#endif
 
 namespace lmms {
 FileSearch::FileSearch(const QString& filter, const QStringList& paths, const QStringList& extensions,