Win32 fixes for farstream

[Tomasz Wasilczyk]

Hi,

I've been working recently on win32 build of farstrean (0.1.x branch).
I've made some
fixes, that I think should be pushed to upstream. I believe, most of
these can be easily applied to 0.2.x branch.

The main goal of this patch is to make mingw32 build possible and free
of warnings.

The patch:
https://dl.dropboxusercontent.com/u/5448886/contrib/mingw32-farstream.patch

The whole OBS project is accessible here:
https://build.opensuse.org/project/show?project=home%3Atomkiewicz%3Agst0

Waiting for feedback,
Tomek