Semantic analysis and CodeGen support for C11's _Noreturn. This is modeled as
an attribute for consistency with our other noreturn mechanisms.

llvm-svn: 173898
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index f9ad946..ed2a0c3 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -1812,6 +1812,7 @@
 
 bool FunctionDecl::isNoReturn() const {
   return hasAttr<NoReturnAttr>() || hasAttr<CXX11NoReturnAttr>() ||
+         hasAttr<C11NoReturnAttr>() ||
          getType()->getAs<FunctionType>()->getNoReturnAttr();
 }