Don't #include <stdio.h> when tests don't need it, or use clang instead of clang-cc when they do.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89070 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGenObjC/messages-2.m b/test/CodeGenObjC/messages-2.m
index 02dbd01..5cf4d2d 100644
--- a/test/CodeGenObjC/messages-2.m
+++ b/test/CodeGenObjC/messages-2.m
@@ -1,6 +1,6 @@
 // RUN: clang-cc --emit-llvm -o %t %s
 
-#include <stdio.h>
+int printf(const char *, ...);
 
 @interface Root
 @end