valid declarations and doesn't give an error for autoconf-style invalid
redeclarations. This isn't quite ideal, but I don't see any other way
easy way to handle it. (The only thing I can think of that's reasonably
general is adding a new builtin type FILETy which is only compatible
with a type equivalent to FILE, and that seems like overkill.)
llvm-svn: 72760
Eli Friedman