build on FreeBSD

[danniculescu]

Fails to validate the platform on FreeBSD due to SONAMES dict being limited to Linux and Darwin. Adding a key for FreeBSD allows a successful install.
in __init__.py:
SONAMES = { "Linux": "libxcb.so.1", "Darwin": "libxcb.dylib", "FreeBSD": "libxcb.so.1", }

[tych0]

Thanks for the report. I think rather than having to add things on a case-by-case basis, I should have just gone with unix-like sonames being the default, so it wouldn't break things for folks like you. I've just pushed a patch to do that now.

Cheers!