Make sure we don't get double defines here for __MINGW_EXTENSION.


git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@3955 4407c894-4637-0410-b4f5-ada5f102cad1

mingw-w64-headers/crt/_mingw_mac.h

diff --git a/mingw-w64-headers/crt/_mingw_mac.h b/mingw-w64-headers/crt/_mingw_mac.h
index dbf4f67..46cb24e 100644
--- a/mingw-w64-headers/crt/_mingw_mac.h
+++ b/mingw-w64-headers/crt/_mingw_mac.h
@@ -116,6 +116,7 @@
 #define __WINT_TYPE__  unsigned short
 #endif
 
+#undef __MINGW_EXTENSION
 #if defined(__GNUC__) || defined(__GNUG__)
 #define __MINGW_EXTENSION	__extension__
 #else