crt: Mark _wassert with __MINGW_ATTRIB_NORETURN

This avoids warnings from Clang, pointing out that this function
could be marked noreturn.

Signed-off-by: Martin Storsjö <martin@martin.st>

mingw-w64-crt/misc/wassert.c

diff --git a/mingw-w64-crt/misc/wassert.c b/mingw-w64-crt/misc/wassert.c
index d342048..b43ddaf 100644
--- a/mingw-w64-crt/misc/wassert.c
+++ b/mingw-w64-crt/misc/wassert.c
@@ -8,6 +8,7 @@
 #include <stdlib.h>
 
 /* _wassert is not available on XP, so forward it to _assert if needed */
+__MINGW_ATTRIB_NORETURN
 static void __cdecl mingw_wassert(const wchar_t *_Message, const wchar_t *_File, unsigned _Line)
 {
     char *message = NULL, *file = NULL;