demandimportpy3: only use lazy extension loader on Python 3.6+...
demandimportpy3: only use lazy extension loader on Python 3.6+
There was an inline comment denoting a bug in the lazy extension
loader on Python 3.5 which prevents it from working there. But the
code was not conditional on the Python version.
The result of this was a myriad of failures on Python 3.5 due to
getattr() and friends not working on lazy extension modules.
By making extension modules non-lazy on Python 3.5, we reduce the
number of test failures from 48 to 22 on that Python version.
