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/CodeGen/mandel.c b/test/CodeGen/mandel.c
index 27993f0..9d7956c 100644
--- a/test/CodeGen/mandel.c
+++ b/test/CodeGen/mandel.c
@@ -25,7 +25,7 @@
 
 #define I 1.0iF
 
-#include <stdio.h>
+int putchar(char c);
 
 volatile double __complex__ accum;