#3986 replacing string and types call (like in the Py3k branch), and put exec_msg call at the right place

the only user of this is Lib/distutils/tests/test_build_ext.py (in order
to find the source for xxmodule.c).  I'm not sure if other platforms
need similar tweaks, I'm not brave enough to attempt it without being
able to test.

Since "srcdir" should now be defined on all platforms, use it to
find the module source.

directory other than the source directory, simplify the test code in
test_sysconfig.py.

the source.  Also, define 'srcdir' on non-posix platforms.

Reviewed by Amaury Forgeot d'Arc.

universal builds that are presented by the configure script.

Reviewed by Benjamin Peterson.

later test failures.  As discussed on #python-dev

non-ascii characters and Unicode in setup.py meta-data.

from the same python instance, some environment variables (LIB, INCLUDE)
would grow without limit.

Tested with these statements:
    distutils.ccompiler.new_compiler().initialize()
    print os.environ['LIB']
But I don't know how to turn them into reliable unit tests.

Be less strict when parsing these version numbers,
they don't necessarily follow the python numbering scheme.