compile farm issues

[Paul Zimmermann]

       Hi,

while checking a new release candidate for GNU MPC on the compile farm,
I found no issue in MPC, but a few issues with GMP:

cfarm119: I found no working compiler (this is not an issue with GMP,
but if you find one, please tell me)

cfarm210: make check from GMP fails (FAIL:  8), idem with the latest snapshot
	  gmp-6.3.0-20260302071043
The C compilers are quite old (gcc version 9.5.0 or cc: Sun C 5.9 SunOS_sparc)
and I don't know if there are some newer versions available somewhere.

cfarm240: gmp-6.3.0 says:
checking build system type... Invalid configuration 'aarch64c-unknown-freebsd15.0': machine 'aarch64c-unknown' not recognized
idem with gmp-6.3.0-20260302071043
The compiler is clang version 15.0.0.

Paul