The changes to Doc/library/unittest.mock.rst are almost entirely a
selective backport of the 3.5 page.

Merge with 3.4: Issue #24259: tarfile now raises a ReadError if an archive is truncated inside a data segment.

on OS X.  Original patch by André Freitas.

Remove build condition to prevent old strings hanging around
Add -h option to build.bat

- update installer ReadMe file
- suppress installer per-file byte-compilation messages to system log
- speed up installer byte-compilation
- isolate ensurepip install from user site-packages