re-merge r69268 (issue4804) from trunk: Now that the C runtime assertions are not silenced any more, we must provide checks for the format string of strftime
re-merge r69268 (issue4804) from trunk:
Now that the C runtime assertions are not silenced any more,
we must provide checks for the format string of strftime

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator