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.
The new msvc9compiler module supports VS 2005 and VS 2008. I've also fixed build_ext to support PCbuild8 and PCbuild9 and backported my fix for xxmodule.c from py3k. The old code msvccompiler is still in place in case somebody likes to build an extension with VS 2003 or earlier.
I've also updated the cygwin compiler module for VS 2005 and VS 2008. It works with VS 2005 but I'm unable to test it with VS 2008. We have to wait for a new version of cygwin.