Fix PR9624 by explicitly disabling uninitialized warnings for direct self-init:

  int x = x;

GCC disables its warnings on this construct as a way of indicating that
the programmer intentionally wants the variable to be uninitialized.
Only the warning on the initializer is turned off in this iteration.

This makes the code a lot more ugly, but starts commenting the
surprising behavior here. This is a WIP, I want to refactor it
substantially for clarity, and to determine whether subsequent warnings
should be suppressed or not.

llvm-svn: 128894