[Python-ideas] Reduce platform dependence of date and time related functions

[random832 at fastmail.us]

I have an addition to this proposal: struct_time should always provide
tm_gmtoff and tm_zone, gmtime should populate them with 0 and GMT*, and
if the platform does not provide values localtime should populate them
with timezone or altzone and values from tzname depending on if isdst is
true after calling the platform localtime function.

*The current practice of the reference code of the "tz" project and of
at least glibc is to use GMT. If anyone has an argument that it should
be UTC or some other value on some platforms, please speak up.