Solaris ships Python versions 2.7, 3.4 and 3.5 at present.  For 2.7,
we ship both 32-bit and 64-bit versions; for 3.4 and 3.5 we only ship
64-bit versions.  For 2.7, we ship /usr/lib/python2.7/config/ with the
usual suspects (Makefile, Setup.config, config.c, install-sh, python.o,
Setup, Setup.local, config.c.in, makesetup) thereunder for the 32-bit
version but for the 64-bit version, we don't ship the equivalent
directory at all.  For 3.4 and 3.5, we ship
/usr/lib/python3.[45]/config-3.[45]m/ with its usual suspects.  We had
a bug filed about the discrepancy in shipping the 32-bit but not the
64-bit version of that directory for 2.7.  An investigation suggested
the directory is not used for 2.7, nor did it seem used (per docs we
could find) for 3.x.  But testing revealed it is used for 3.x, as our
builds failed, e.g.:

error: invalid Python installation: unable to open
    /usr/lib/python3.4/config-3.4m/Makefile (No such file or directory)

when we removed the config-3.[45]m directories.  OK, fine, it was an
experiment, so we'll keep the directories.  But it was not clear to
us from the docs we could find, such as:
    https://docs.python.org/3.6/extending/extending.html
exactly how the config directory is used.  This is a documentation
enhancement request to clarify how the config directory is used.