gmp problem under darwin powerpc

[Torbjorn Granlund]

It turned out this was simple to fix.  I pushed a change to both the
gmp-5.0 repo and the mainline repo.

It was a register clobbering issue affecting PIC builds on ELF and
Darwin system, making operands of >= 20 words get an incorrect loop trip
count.

If you pull the new file, your builds should work again without te speed
degradation resulted from removing the offending file.  If you do this,
please send feedback to this list.

-- 
Torbjörn