[Bf-committers] breaking cygwin compile

[Rob Haarsma]

Thank you Chris Burt for fixing my commit!

Apologies for breaking the cygwin compile, but in buttons_scene.c
there were just too many platform specific dependancies piled up
together (AVIcodecs/Quicktime/Apple/Windows/QT linux).
The result was a malicious #ifdef construction which only allowed
AVI codec rendering if WITH_QUICKTIME was defined (!?).

I tried to clean up the compile dependancies, but doing so I forgot
about the FREE_WINDOWS port. I cannot test the fix since I work
on msvc, but I'm confident that it is ok.

Regards,
Rob