arm-elf multilib issues

[Paul Brook]

> Do we want to enable more multilibs in arm-elf?

Almost certainly not. As far as I'm concerned arm-elf is obsolete, and in 
maintenance only mode. You should be using arm-eabi.

IMHO building lots of multilibs by default significantly increases toolchain 
size and build time for little actual benefit. ARM CPUs are generally 
backwards compatible and we only have one important ABI variant, so very few 
multilibs are required for a functional toolchain. Anybody who cares about 
optimized runtime libraries probably wants tuning for their exact setup, 
rather than whatever arbitrary selections you're going to choose.

Paul