Besides other issues, this should fix an integer overflow breaking IPv6 address
aquisition after a runtime of 50 days.

This *should* fix the build on non-Linux systems like MacOS X.

This updates OpenWRT and rebases our patches.

Furthermore, the mac80211 module is removed as currently the Attitude Adjustment
main repo has a newer version (and some fixes that aren't in the backport repo).

Also, update odhcp6c from Barrier Breaker.