Message 69298 - Python tracker

This new patch adds re.ASCII in all sensitive places I could find in the
stdlib (except lib2to3 which as far as I understand is maintained in a
separate branch, and even has its own copy of tokenize.py...).

Also, I didn't get an answer to the following question on the ML: should
an inline flag "(?a)" be introduced to mirror the existing "(?u)" - so
as to set the ASCII flag from inside a pattern string.