Added a new attribute, objc_root_class, which informs the compiler when a root class is intentionally declared.
The warning this inhibits, -Wobjc-root-class, is opt-in for now. However, all clang unit tests that would trigger
the warning have been updated to use -Wno-objc-root-class. <rdar://problem/7446698>

llvm-svn: 154187
diff --git a/clang/test/SemaObjC/stand-alone-implementation.m b/clang/test/SemaObjC/stand-alone-implementation.m
index c33b66a..6fa9b4b 100644
--- a/clang/test/SemaObjC/stand-alone-implementation.m
+++ b/clang/test/SemaObjC/stand-alone-implementation.m
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class %s
 // radar 7547942
 // Allow injection of ivars into implementation's implicit class.