I propose (for post 2.3) we expose a lowlevel
setlocale() for diagnostic purposes.  Specifically, I
propose that release builds support only querying the
current locale, but Py_DEBUG builds be capable of
bypassing Python completely.

This is somewhat complementary to [ 774665 ] making
Python LC_NUMERIC agnostic

This would be extremely good for Windows - hence my
patch adds such a method to the "msvcrt" module. 
However, I believe it worthy of consideration for
locale itself, seeing as it is impossible to have
Python-related side effects in release builds.  For
people running debug builds (or capable of switching to
them) it provides invaluable help.

Assigning to Tim to pronounce on.  Either reject it,
accept for msvcrt (and I will check it in post 1.3) or
accept in principle for _locale, then assign back.