Message 144637 - Python tracker

It's more a straight duplicate of #12973, but the underlying cause
(signed integer overflow) is the same. For people who are finding
this via a search engine: A lot of bugs have been fixed in #12973,
but even if the test suite passes without -fwrapv it is *still* recommended to use -fwrapv.


Could anyone test if the attached patch works for llvm-gcc?