tailoring for universal builds by factoring out common OS X-specific
customizations from sysconfig, distutils.sysconfig, distutils.util,
and distutils.unixccompiler into a new module _osx_support that can
eventually also be used by packaging.

Patch by Flávio Ribeiro.

Patch by Serhiy Storchaka.

visible and to place it with other micro-benchmarks (e.g.
stringbench).

This should make the Linux distros happy as it is now easier to leave
importlib's tests out of their base Python distribution.

of importing a symlinked package.

no difference anymore between __import__ and importlib.__import__.

Patch by Flávio Ribeiro.

Patch by Flávio Ribeiro.

Close #15386: There was a loophole that meant importlib.machinery and imp would sometimes reference an uninitialised copy of importlib._bootstrap

the source line.  Such errors can't be reported anyway.  This makes error
reporting work, even if the "io" module can't be loaded.

Patch by Julia Lawall.

Patch by Julia Lawall.

Patch by Atsuo Ishimoto.