Adaptive quantization help--variance masking

I got bored and decided I would port x264's new VAQ to Xvid.

After 15 minutes, I got this patch: http://pastebin.com/f609010fc .  It just
overwrites the lumimasking code.

However, all my attempts to compile Xvid result in a library that just does
ordinary lumimasking, even though I've overwritten the code.  This isn't a
"duplicate library" issue; I have confirmed that it is indeed my compiled
version of Xvid that is being used.

What could the problem be--and could any other developer try throwing in
this patch and seeing if it works?

Note the "strength" parameter can be varied arbitrarily.  It does what you
think it does.

Dark Shikari, x264 developer