add a check for gcc to the constants recently added for the msvc port. They seem to cause problems on some gcc's but not mine.

svn path=/trunk/; revision=19539

reactos/lib/crt/include/float.h

@@ -91,9 +91,11 @@
 #define _FPE_STACKUNDERFLOW	0x8b
 #define _FPE_EXPLICITGEN	0x8c    /* raise( SIGFPE ); */
 
+#ifdef __GNUC__
 #define DBL_MAX_10_EXP  308  
 #define S_IFIFO			-1
 #define UINT64_MAX	0xffffffffffffffff
+#endif
 
 #ifndef RC_INVOKED