[PATCH] D45383: Limit types of builtins that can be redeclared.

[Saleem Abdulrasool via Phabricator via cfe-commits]

compnerd added a comment.

I know that the Windows SDK definitely declares the `__va_start` function.  Did you try building something like swift against the Windows SDK with this change?


https://reviews.llvm.org/D45383