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/FrontendOptions.cpp b/clang/lib/Frontend/FrontendOptions.cpp
index 9ede674..6a82084 100644
--- a/clang/lib/Frontend/FrontendOptions.cpp
+++ b/clang/lib/Frontend/FrontendOptions.cpp
@@ -25,6 +25,8 @@
     .Case("mii", IK_PreprocessedObjCXX)
     .Cases("C", "cc", "cp", IK_CXX)
     .Cases("cpp", "CPP", "c++", "cxx", "hpp", IK_CXX)
+    .Case("cppm", IK_CXX)
+    .Case("iim", IK_PreprocessedCXX)
     .Case("cl", IK_OpenCL)
     .Case("cu", IK_CUDA)
     .Cases("ll", "bc", IK_LLVM_IR)