the logic for computing __func__ and friends is really broken:

the logic for computing __func__ and friends is really broken:
the type assigned by sema (and is visible with sizeof(__func__) for
example) has nothing to do with what codegen ends up producing.
We should eventually add a method on PredefinedExpr to handle this.
In the meantime, just set up some framework and add some fixme's.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69872 91177308-0d34-0410-b5e6-96231b3b80d8