Don't rely on end of line. Open files in text mode, not in binary mode.

rounding

used.

* initialize numerator on overflow error ensure that numerator is smaller than
* denominator.

Issue #23517: the change broke test_datetime. datetime.timedelta() rounding
mode must also be changed, and test_datetime must be updated for the new
rounding mode (half up).

datetime.datetime.utcfromtimestamp() now rounds to nearest with ties going away
from zero, instead of rounding towards minus infinity (-inf), as Python 2 and
Python older than 3.3.

Change also _PyTime_FromSeconds() assertion to ensure that the _PyTime_t type
is used.

Move code to convert double timestamp to subfunctions.

Patch from Mattip.