Add support for Microsoft __interface keyword. An __interface class is basically a normal class containing just pure virtual functions. No urgency to enforce that restriction in clang for now, so make __interface an "class" alias.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130290 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed