extensions with msvc9compiler.

ignores the '-isysroot' option on OSX when the
corresponding SDK is not installed.

This ensures that the user can compile extensions
on OSX 10.6 using the Python.org installer and a
default installation of Xcode.

improved distutils test coverage: now the DEBUG mode is covered too (will help fix the issue #6954 in py3k branch)

to --with-universal-archs

and --with-universal-archs=3-way (issue6245)

added more test coverage for distutils.filelist to prevent regressions when fnmatch or re are changed

fixed how fnmatch.translate is used (since it has changed in r74475 for #6665). Now the code is not harcoding the usage of $ anymore

Issue #6545: Removed assert statements in distutils.Extension, so the behavior is similar when used with -O