Bug#780186: GMP doesn't manage memory correctly

[Julien Puydt]

Package: gmp
Version: 2:6.0.0+dfsg-6

Hi,

the sagemath software is using MPIR, but we're trying to package it for 
debian using the default lib for multi-precision arithmetic : GMP.

Sagemath uses mp_set_memory_functions to override the default memory 
management and make it better for their purpose (trigger their error 
handling), but there are places where gmp still calls its own functions!

And we have a failing test in their suites where an abort is triggered, 
because _mpz_realloc in mpz/realloc.c is called instead of the 
sagemath-provided realloc.

GMP shouldn't call its own realloc if a better one has been provided.

Thanks,

Snark on #debian-science