-current broken on pre-PPro machines (w/ work around)

[John-Mark Gurney]

Just a warning to others so they don't hit the same issue I did, and
spend time trying to figure it out.  clang (in -current) does not
compile code properly for pre-PPro machines... Compiled output includes
the cmov instructions...

This affects both loader, and kernel, so if you update loader, you'll
see a few spins, and the machine will probably reset... if you use an
older loader, your kernel will fault a/ an illegal instruction...

If you want to run -current on one of these machines, make sure you set
WITHOUT_CLANG_IS_CC= for *BOTH* buildworld and installworld so that you
use gcc instead of clang...

A bug has been filed:
http://llvm.org/bugs/show_bug.cgi?id=15115

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."