Frontend: Add basic -H support.
 - I didn't implement the GCC "multiple include guard" detection parts, because
   it doesn't seem useful or obvious.

llvm-svn: 111983
diff --git a/clang/test/Frontend/Inputs/test3.h b/clang/test/Frontend/Inputs/test3.h
new file mode 100644
index 0000000..92ff4b8
--- /dev/null
+++ b/clang/test/Frontend/Inputs/test3.h
@@ -0,0 +1 @@
+int y;