EXT/GMP/GMP.C: IN FUNCTION ‘ZIF_GMP_RANDOM’:
EXT/GMP/GMP.C:1399:69: ERROR: ‘__GMP_BITS_PER_MP_LIMB’ UNDECLARED (FIRST USE IN THIS FUNCTION)
EXT/GMP/GMP.C:1399:69: NOTE: EACH UNDECLARED IDENTIFIER IS REPORTED ONLY ONCE FOR EACH FUNCTION IT APPEARS IN

This time it's PHP bug #50990. In one of comments there susan dot smith dot dev at gmail dot com suggested solution which works and does its magic:

I solved replacing the outdated __GMP_BITS_PER_MP_LIMB defined constant with GMP_LIMB_BITS. The latter is present in all previous versions, and MPIR define it too.
You have to edit file ext/gmp/gmp.c and replace one occurence of __GMP_BITS_PER_MP_LIMB with GMP_LIMB_BITS, in my case it was in line 1399.