Support for C1x _Atomic specifier (see testcase).  This is primarily being committed at the moment to help support C++0x <atomic>, but it should be a solid base for implementing the full specification of C1x _Atomic.

Thanks to Jeffrey Yasskin for the thorough review!

llvm-svn: 141330
diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index 2b7250f..a2aa1b30 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -619,7 +619,8 @@
   switch (DS.getTypeSpecType()) {
   case TST_typename:
   case TST_typeofType:
-  case TST_underlyingType: {
+  case TST_underlyingType:
+  case TST_atomic: {
     QualType T = DS.getRepAsType().get();
     if (!T.isNull() && T->containsUnexpandedParameterPack())
       return true;