[Cython] vcvarsall.bat error on win32 with mingw when using cython_inline

[Dave Hirschfeld]

Hi cython devs,
I got the "unable to find vcvarsall.bat" error when using cython_inline when 
trying to compile with mingw. Using cython normally (creating a setup.py file) 
worked fine however.

I was able to fix the problem for me by changing inline.py to parse the config 
files before building the extension. I've created a pull request with my changes:

https://github.com/cython/cython/pull/129

Apologies if I haven't used the appropriate workflow - I'm fairly new to git and 
this is my first pull request!

HTH,
Dave