[cairo] Win32 Building

[Antoine Azar]

> Travis, if we are going to assume a user with git on their Windows
machine, then what other tools can we also assume they have? A bash
interpreter? Anything else?

I have the mozilla-build and msysgit installed and it's providing me with
pretty much all I need.

I'm now fighting with CRT errors in the win32 build, seems that some stuff
is being build with the static runtime and others with the dynamic runtime.

Antoine