Changes for GMP 6.1.2

[Torbjörn Granlund]

I think we should make 6.1.2, mainly for mini-gmp but also with a bunch
of GMP changes listed below.

I'd like to ask the mini-gmp changes to either copy the current code to
the gmp-6.1 repo, or if you prefer cherry-pick the mini-gmp changes you
want.

The Makefile.am changes for mini-gmp are missing here.  We simply need
to merge from the current version in the corresponding mini-gmp commit.

What about ChangeLog wrt mini-gmp?  I'd suggest we keep one, and simply
put the new mini-gmp/ChangeLog entries in the top-level ChangeLog.

https://gmplib.org/repo/gmp/raw-rev/1d7e1bd08532
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/82a55ed8bbd0
https://gmplib.org/repo/gmp/raw-rev/56f4a38cb31a
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/504ea841a52b
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
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