Index: test/CodeGen/builtins.c
===================================================================
--- test/CodeGen/builtins.c	(revision 84183)
+++ test/CodeGen/builtins.c	(working copy)
@@ -116,8 +116,10 @@
 }
 
 
-
+// strcat is implicit for VC++.
+#if !defined(_M_IX86) && !defined(_M_X64)
 void strcat() {}
+#endif
 
 void foo() {
  __builtin_strcat(0, 0);