Original patch by Tshepang Lekhonkhobe.

packaging.util.check_environ will define HOME and PLAT if they don’t exist; for
some reason, it does not define PLAT when running the tests from a checkout (so
no regrtest warning) but does when running from an installed Python.

Cleaning up the envvar in test_dist fixes the warning on my machine, but I
suspect that a test runner using a different order to run files or running them
in parallel may have PLAT defined in its environment because of another test.
Quite a lot of code ends up calling check_environ; maybe we should just clean
up PLAT in every test.  For now I’m doing this simple fix, we’ll see if we get
bug reports.

The code does not write checksum or file length for .pyc and .pyo in the RECORD
file, in compliance with PEP 376, but the test forgot to take .pyo into
account.  This was not caught because there were no .pyo in the checkout, but
after installing there are .pyo files created by compileall, and the test picks
them up.

The example C extension used the “three.fast_taunt” name, but no “three” parent
was defined in the setup.cfg.  This did not cause a failure nor even print a
warning, we may want to change that.

By changing to the Windows GetFileAttributes API in nt._isdir we can figure
out if the path is a directory without opening the file via os.stat. This has
the minor benefit of speeding up os.path.isdir by at least 2x for regular
files and 10-15x improvements were seen on symbolic links (which opened the
file multiple times during os.stat). Since os.path.isdir is used in
several places on interpreter startup, we get a minor speedup in startup time.

By changing to the Windows GetFileAttributes API in nt._isdir we can figure
out if the path is a directory without opening the file via os.stat. This has
the minor benefit of speeding up os.path.isdir by at least 2x for regular
files and 10-15x improvements were seen on symbolic links (which opened the
file multiple times during os.stat). Since os.path.isdir is used in
several places on interpreter startup, we get a minor speedup in startup time.

Lehtinen.

children and raises BrokenProcessPool in such a situation.  Previously it
would reliably freeze/deadlock.

Extract of the commit message:

  Fix usage of :option: in the docs (#9312).

  :option: is used to create a link to an option of python, not to mark
  up any instance of any arbitrary command-line option.  These were
  changed to ````.

Such tests are IMO easier to read if both operators are grouped.

This helps debugging in case of trailing blanks and such things.

Namely: use default arguments instead of explicit empty string; use multiple
arguments instead of building strings.

temporary symbolic link.

Found by LLVM/clang 2.9.

Found by LLVM/clang 2.9.

prevent accidental assignment.

Silences a warning from LLVM/clang 2.9.

always appended to the include directories regardless of whether it
was already in the list of directories. This could cause issue if
sqlite was installed in the same location as another install of
Python. Now a check is done to make sure the directory is not included
twice.

instead of an active loop (while True: pass) to limit race conditions.