The clean command line compiler clm uses timestamps of dcl, icl, abc and o files
to decide what must be rebuild.  However as for chroot builds, all of the
library files will have equal timestamps, this leads to clm trying to rebuild
the library modules distributed with the Clean installation every time a user
compiles any file, which fails ue to the absence of write permission on the Nix
store.

This patch changes the freshness check to use less than instead of less than or
equal to in order to avoid this.

--- b/src/clm/clm.c
+++ a/src/clm/clm.c
@@ -250,7 +250,7 @@
 		|| (t1.dwHighDateTime==t2.dwHighDateTime && (unsigned)(t1.dwLowDateTime)<=(unsigned)(t2.dwLowDateTime)))
 #else
 	typedef unsigned long FileTime;
-#	define FILE_TIME_LE(t1,t2) (t1<=t2)
+#	define FILE_TIME_LE(t1,t2) (t1<t2)
 #endif
 
 typedef struct project_node {