And "IDLE: fix some RessourceWarning, reuse tokenize.open()"

On error, call(), check_call(), check_output() and getstatusoutput() functions
of the subprocess module now kill the process, read its status (to avoid
zombis) and close pipes.

Suggested by Terry J. Reedy in #12298.

sigaltstack(2) doesn't work when linked with pthread.

mapped to POSIX errno ENOTDIR (previously EINVAL).

mapped to POSIX errno ENOTDIR (previously EINVAL).

Text adapted from the PEP.  Addition requested by Terry J. Reedy on
2011-02-23 on python-dev.

This was discussed some months ago on python-dev.  Having tons of links
to the definition of True would be annoying, contrary to links to e.g.
the nonlocal or with statements doc.

The right-hand part in [extension: foo] is now used as the name of the
extension module.  (I changed the separator from = to : and allowed
whitespace to make the sections look nicer.)

rstlint complains about packaging docs but I’m working on those in
another patch.

This huge module is the heir of six distutils modules, and contains
a number of miscellaneous functions.  I have attempted to help readers
of the source code with an annoted __all__.  Removed or deprecated
functions have been removed from the documentation; I’m working on
another patch to document the remaining public functions.

For the curious:

The unzip_file and untar_file were used by (or intended to be used by)
“pysetup install path/to/archive.tar.gz”, but the code presently used
shutil.unpack_archive and an helper function, so I just deleted them.
They’re still in the repository if we need them in the future.

The find_packages function is not used anymore but I want to discuss
module and package auto-discovery (in “pysetup create”) again before
removing it.

subst_vars now lives in sysconfig; rfc822_escape is inlined in
packaging.metadata.  Other functions are for internal use only, or
deprecated; I have left them out of __all__ and sprinkled TODO notes
for future cleanups.

This is a temporary kludge and all is well in 3.3.