Extend the __declspec(dll*) attribute to cover ObjC interfaces. This was
requested by Microsoft for their ObjC support. Cover both import and export.
This only adds the semantic analysis portion of the support, code-generation
still remains outstanding. Add some basic initial documentation on the
attributes that were previously empty. Tweak the previous tests to use the
relative expected-warnings to make the tests easier to read.
llvm-svn: 275610
Saleem Abdulrasool