Fix compiler_builtins.m test to not rely on including system stdlib.h and malloc.h

Importing _Builtin_intrinsics.sse and avx would transitively pull in those
headers, and the test would fail when building in an environment where
they were not available on the include path.

This fixes PR20995 for me.

Differential Revision: http://reviews.llvm.org/D7112

llvm-svn: 226754
diff --git a/clang/test/Modules/Inputs/System/usr/include/malloc.h b/clang/test/Modules/Inputs/System/usr/include/malloc.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/clang/test/Modules/Inputs/System/usr/include/malloc.h
diff --git a/clang/test/Modules/Inputs/System/usr/include/stdlib.h b/clang/test/Modules/Inputs/System/usr/include/stdlib.h
new file mode 100644
index 0000000..a1bf1a8
--- /dev/null
+++ b/clang/test/Modules/Inputs/System/usr/include/stdlib.h
@@ -0,0 +1 @@
+typedef __SIZE_TYPE__ size_t;
diff --git a/clang/test/Modules/compiler_builtins.m b/clang/test/Modules/compiler_builtins.m
index 4b8cb5b..f120bcf 100644
--- a/clang/test/Modules/compiler_builtins.m
+++ b/clang/test/Modules/compiler_builtins.m
@@ -1,6 +1,6 @@
 // RUN: rm -rf %t
-// RUN: %clang -fsyntax-only -fmodules -fmodules-cache-path=%t -D__need_wint_t %s -Xclang -verify
-// RUN: %clang -fsyntax-only -std=c99 -fmodules -fmodules-cache-path=%t -D__need_wint_t %s -Xclang -verify
+// RUN: %clang -fsyntax-only -fmodules -fmodules-cache-path=%t -D__need_wint_t %s -I%S/Inputs/System/usr/include -Xclang -verify
+// RUN: %clang -fsyntax-only -std=c99 -fmodules -fmodules-cache-path=%t -D__need_wint_t %s -I%S/Inputs/System/usr/include -Xclang -verify
 // expected-no-diagnostics
 
 #ifdef __SSE__