Also provide a sample Install Certificates command script to install a
set of root certificates from the third-party certifi module.

Issue #27213.

Revert change "Issue #27213: Reintroduce checks in _PyStack_AsDict()", pushed
by mistake.

It seems like at least 2 buildbots need more than 15 minutes per test file.
Example with "AMD64 Snow Leop 3.x":

    10 slowest tests:
    - test_tools: 14 min 40 sec
    - test_tokenize: 11 min 57 sec
    - test_datetime: 11 min 25 sec
    - ...

Issue #27744:

* Release msg.msg_iov memory block.
* Release memory on PyMem_Malloc(controllen) failure

Issue #27744:

* PEP 7: add {...} around if blocks
* assign variables and then check their value in if() to make the code easier
  to read and to debug.

(Patch by Duane Griffin.  Reviewed and approved by Stefan Behnel.)

Patch by Roger Serwy, updated by Bayard Randel.

Patch by Roger Serwy, updated by Bayard Randel.

Patch by wim glenn.

Patch adapted from https://github.com/ghaering/pysqlite/commit/9b79188edbc50faa24dc178afe24a10454f3fcad