guix/gnu/packages/patches/gcc-4.9.3-mingw-gthr-default.patch

--- a/libgcc/config/i386/gthr-win32.h	2016-03-30 07:45:33.388684463 +0200
+++ b/libgcc/config/i386/gthr-win32.h	2016-03-30 15:51:24.123896436 +0200
@@ -30,7 +30,7 @@

 /* Make sure CONST_CAST2 (origin in system.h) is declared.  */
 #ifndef CONST_CAST2
-#define CONST_CAST2(TOTYPE,FROMTYPE,X) ((__extension__(union {FROMTYPE _q; TOTYPE _nq;})(X))._nq)
+#define CONST_CAST2(TOTYPE,FROMTYPE,X) ((TOTYPE)X)
 #endif

 /* Windows32 threads specific definitions. The windows32 threading model