gmp 6.2.0 test failures on sparc64-solaris10

[Bruno Haible]

Marc Glisse wrote:
> > * The ‘configure’ options you used when building GMP, if any.
> >
> > No options, just './configure'.
> > The environment variable CC is set to 'cc -xarch=v9', as recommended in
> > https://gmplib.org/manual/ABI-and-ISA .
> 
> ?
> The manual says to set ABI to 64.

No, it doesn't say that I *must* set ABI.

In https://gmplib.org/manual/Build-Options it says
  "By default GMP chooses the best ABI available, but a particular ABI can be
   selected."

In https://gmplib.org/manual/ABI-and-ISA it says
  "By default GMP chooses the best ABI available for a given system, and this
   generally gives significantly greater speed. But an ABI can be chosen
   explicitly..."

This is good. For consistency with other GNU packages, which accept CC,
CFLAGS, CPPFLAGS, and LDFLAGS variables at configure time [1] and deduce
as much configuration details from these.

I've built gmp-6.2.0 on many platforms, and on most of them setting ABI
was not necessary, if I set CC appropriately like I do for the other GNU
packages.

[1] https://www.gnu.org/software/automake/manual/html_node/Standard-Configuration-Variables.html