Introduce a module import declaration, so that we properly represent, e.g.,

  __import_module__ std.vector;

in the AST.

llvm-svn: 145725
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 0905c4b..0e8468f 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2335,6 +2335,7 @@
   case Decl::TypeAliasTemplate:
   case Decl::NamespaceAlias:
   case Decl::Block:
+  case Decl::Import:
     break;
   case Decl::CXXConstructor:
     // Skip function templates