vla's aren't C90, use alloca instead.

llvm-svn: 46057
diff --git a/llvm-gcc-4.0/gcc/config/darwin.h b/llvm-gcc-4.0/gcc/config/darwin.h
index fe563bf..78ee32e 100644
--- a/llvm-gcc-4.0/gcc/config/darwin.h
+++ b/llvm-gcc-4.0/gcc/config/darwin.h
@@ -1386,7 +1386,7 @@
 #define ASM_DECLARE_UNRESOLVED_REFERENCE(FILE,NAME)			\
     do {								\
 	 if (FILE) {							\
-           char Buffer[strlen(NAME)+30];				\
+           char *Buffer = alloca(strlen(NAME)+30);			\
 	   if (MACHOPIC_INDIRECT)					\
              sprintf(Buffer, "\t.lazy_reference %s", NAME);		\
 	   else								\