Fat binaries for modules?

[reticulatedpines]

ARMv7 cams have Thumb, but modules are built only as ARMv5 / ARM, for compatibility reasons. We have a custom loader via tcc anyway, so we could perhaps build these as fat binaries, containing a Thumb and non-Thumb build, with the loader detecting the best choice to load.

The Thumb builds have quite a lot less memory footprint (and presumably some speed improvement, as well as lower I-cache pressure).

ARMv5te supports Thumb (just 1, not 2?) so it might be an option there as well. This might mean three builds per file is optimal, but we have a lot more disk space than memory so I think this would be fine.