Oh I entirely agree with you on both the previous post and this one, don't get me wrong - both are good at what they do - the former gives much more actually "useful" space on-device, the latter gives you a chroot sdk environment.

It's just that each of those doesn't directly help the OP's question: how to get optified packages by default when running something like "make install". (Although I think you could put a chroot inside /opt/something and then permanently add that chroot's (s)bin directories to your path, then make install from within the chroot. Since the binaries inside the chroot will still be N900's-Maemo5-runnable, assuming you set up the chroot correctly. Although I'm not sure if I understand chroots right, but I think it should be possible to have a chroot that's just part of the filesystem it's in, rather than a seperate file...? [so all the stuff inside it is visible/runnable even when the chroot isn't running])