The attached patch is a follow up from my previous one. The existing
logic was not handling typedefs as free functions. This was not
causing problems with the existing tests, but does with the microsoft
abi where they have to get a different calling convention.

I will try to refactor this into a method on Declarator in a second.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195050 91177308-0d34-0410-b5e6-96231b3b80d8