More llvm-gcc build breakage

Rev 54193 seems to cause that failure doing a non bootstrap build on
MingW.

+#ifdef __i386__
+extern int VirtualProtect (char *, int, int, int *) __attribute__((stdcall));
+#endif

Do we need this stuff at all? afair, I deleted the whole lines in r47684 to sync libgcc2.c with
mainline gcc.