C++ Modules TS: add frontend support for building pcm files from module
interface files. At the moment, all declarations (and no macros) are exported,
and 'export' declarations are not supported yet.

llvm-svn: 279794
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 97c37de..3154291 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1116,6 +1116,8 @@
       Opts.ProgramAction = frontend::FixIt; break;
     case OPT_emit_module:
       Opts.ProgramAction = frontend::GenerateModule; break;
+    case OPT_emit_module_interface:
+      Opts.ProgramAction = frontend::GenerateModuleInterface; break;
     case OPT_emit_pch:
       Opts.ProgramAction = frontend::GeneratePCH; break;
     case OPT_emit_pth:
@@ -2259,6 +2261,7 @@
   case frontend::EmitObj:
   case frontend::FixIt:
   case frontend::GenerateModule:
+  case frontend::GenerateModuleInterface:
   case frontend::GeneratePCH:
   case frontend::GeneratePTH:
   case frontend::ParseSyntaxOnly: