I like this new framework: I've used it in two of my packages now:
net/aria2 and audio/herrie.  Perhaps you might want to add some sort
of facility to override the usual checks in features.mk and pull in
nbcompat for everything listed in USE_FEATURES?  I'd like a way to
test it to make sure it works as intended and/or I made no mistakes.

Also, I'm unclear how USE_FEATURES.openssl fits into the picture, as I
didn't see anything about suffixed variables in the documentation.

And this is just a brainstorm:  but I have some sort of vague idea
concerning a partial merge of functionaliy between the options
framework and USE_FEATURES, e.g. for selecting direct vs. indirect
rendering in mesa.  Another case could be something, e.g. consider
${MACHINE_ARCH} == "i386".  Then one could do:
USE_FEATURES.${MACHINE_ARCH}=sse2, for instance.
In working on my mesa package, I found that the options framework is a
bit cumbersome for handling all of the possible combinations of
09configurations/architectures.

Opinions?

Cheers,

--Blair

I hope i'm not just talking gibberish because it's so late. ;)