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

llvm-svn: 89070
diff --git a/clang/test/CodeGen/volatile-1.c b/clang/test/CodeGen/volatile-1.c
index 9df11d2..3203326 100644
--- a/clang/test/CodeGen/volatile-1.c
+++ b/clang/test/CodeGen/volatile-1.c
@@ -14,7 +14,7 @@
 } a, b;
 
 //void operator =(volatile struct S&o1, volatile struct S&o2) volatile;
-#include <stdio.h>
+int printf(const char *, ...);
 
 int main() {
   // A use.