From: "Martin v. Löwis" firstname.lastname@example.org I'm personally in favour of supporting "MSYS" as a target system. If you want to do it, I'm willing to review patches, but I'm not willing to do them myself, as I don't use MSYS.
If you believe that MSYS is a target system in a way similar to mingw32, and to cygwin,
actually, MSYS is the package that has the command line tools (i.e. bash, tar, cp, automake, ...) required to be able to compile a native windows binary from a source distribution that is depending on autotools.
I believe it should get the same treatment as mingw32 and cygwin. That means all places that currently deal with either of these two systems should also deal with MSYS in a similar way. What this means in actual code, I don't know.
OTOH, I already fail to follow you in the very first assumption: why is it that you need to change os.sep on MSYS?
"configure" detects what the install-path is (python -c "print os.syspath") which returns C:\Python. MSYS uses a bash shell which does not like "" but needs "/" as os.sep.
Anyways, in the mean time, it's been solved in the m4 files... Maybe it's better to ask the automake guys to support Python with MSYS...