Windows Support

[kageiit]

Make okbuck generate caches/buck files that work on windows

[jbduncan]

I don't know if this is related to the caches or buck files being Windows-unfriendly, but when I try running ./buckw from a Cygwin terminal on Windows 7, it causes the following error message to appear:

chmod: cannot access '': No such file or directory
./buckw: line 247: exec: : not found

[jbduncan]

Heck, it may have something to do with the Gradle setup of the project I'm testing OkBuck against.

I could provide a reproducible example if desired. :)

[jbduncan]

Oh, and it might have something to do with how Buck only supports Windows 10, according to https://buckbuild.com/setup/getting_started.html. :/

[kageiit]

This is unlikely to be supported