2 minor issues on Windows

[Torbjörn Granlund]

Marco Bodrato <bodrato at mail.dm.unipi.it> writes:

  -  *__gmp_rp = (- *__gmp_up) & GMP_NUMB_MASK;
  +  *__gmp_rp = (1 + ~ *__gmp_up) & GMP_NUMB_MASK;

Let's please not do this.

There is some sort of sick competition between certain compilers to have
the most warnings for valid C.  I don't think we should play their game,
and as a result obfuscate the GMP sources.

-- 
Torbjörn
Please encrypt, key id 0xC8601622