On windows, for whatever reason sockets use the SOCKET type which is not
a signed integer. Still, even though it's not a signed integer, -1 is
used to indicate an invalid socket, but the way you use it is via
microsoft's fabulously dumb little INVALID_SOCKET define, so we have to
make librtmp use that instead.
Note that this is a somewhat heavily modified custom version of librtmp.
I modified all the platform specific code that we were using for the
OBS1 to make it platform-independent.
I don't really like the code in this library, but it works well enough,
so I can't really fault anyone for it. It's just very.. unclean. Even
for a C library, quite unclean. Some parts are also a little less safe
than I'd prefer as well.