[Concepts] Concept definitions (D40381)

First in a series of patches to land C++2a Concepts support.
This patch adds AST and parsing support for concept-declarations.

llvm-svn: 365699
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index b0e3b0b..ea52f0c 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -5162,6 +5162,7 @@
   case Decl::UsingShadow:
   case Decl::ClassTemplate:
   case Decl::VarTemplate:
+  case Decl::Concept:
   case Decl::VarTemplatePartialSpecialization:
   case Decl::FunctionTemplate:
   case Decl::TypeAliasTemplate: