Another s64 fix, this time for gcc on 64-bit platforms.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4118 dfc29bdd-3216-0410-991c-e03cc46cb475

include/irrTypes.h

@@ -73,7 +73,11 @@ typedef signed int		s32;
 #ifdef _MSC_VER
 typedef __int64					s64;
 #elif __GNUC__
+#if __WORDSIZE == 64
+typedef long int 				s64;
+#else
 __extension__ typedef long long s64;
+#endif
 #else
 typedef long long				s64;
 #endif