Changes for GMP 6.1.2

[Torbjörn Granlund]

Revised list (some mini-gmp changes had snuck in, as well as a patch for
a file which doesn't exist in 6.1):
  
  https://gmplib.org/repo/gmp/raw-rev/58879634af3c
  https://gmplib.org/repo/gmp/raw-rev/83f0363b194e
  https://gmplib.org/repo/gmp/raw-rev/a1a2870cb3d4
  https://gmplib.org/repo/gmp/raw-rev/7fd121b9e36b
  https://gmplib.org/repo/gmp/raw-rev/7f8a7908c02f
  https://gmplib.org/repo/gmp/raw-rev/44105d8de854
  https://gmplib.org/repo/gmp/raw-rev/a92a2f5b908e
  https://gmplib.org/repo/gmp/raw-rev/2349e1d2f62e
  https://gmplib.org/repo/gmp/raw-rev/48669e3e2368
  https://gmplib.org/repo/gmp/raw-rev/7fbdda08f4ec
  https://gmplib.org/repo/gmp/raw-rev/ca07af6e95ac
  https://gmplib.org/repo/gmp/raw-rev/1890de258348
  https://gmplib.org/repo/gmp/raw-rev/fd5eb90386a9
  https://gmplib.org/repo/gmp/raw-rev/ff2be779bc87
  https://gmplib.org/repo/gmp/raw-rev/7ecdb1bbb5c2

-- 
Torbjörn
Please encrypt, key id 0xC8601622