RFC: turn off arm oabi builds and remove support beyond compat

[matthew green <mrg%eterna.com.au@localhost>]

hi folks.


in an effort to reduce our useless build footprint i think it
is time to turn off building the old arm ABIs, and remove the
support for building them.  this means the "arm" and "armeb"
MACHINE_ARCHs, that use the old arm ELF ABI.

the eabi builds default to building support for old abi and i
am not suggesting removing this, or the kernel support for
running the binaries, but simply only offer eabi builds for
fresh installs.

any objections?


.mrg.