Redo r325502

:U:Mfoo expands to :Mfoo, apparently. Explicit check for CPUTYPE being
defined, and test for it's value not containing *soft* before calling CRTARCH
armhf.

Tested, somewhat. Unfortunately recent changes appear to have affected
cross-builds where it no longer works, per my tests after universe12a being
upgraded from 07/2017 to 11/2017 sources (DESTDIR isn't being used in WORLDTMP;
MK_SYSTEM_COMPILER might be causing issues right now).

MFC after: 1 week
MFC with: r325502
Reported by: imp