various fixes for failing GMP tests #4307

Job	Run time
Compile sysdeps (dripos)	2m 51s
Compile sysdeps (lemon)	2m 23s
Build mlibc (x86_64, mlibc, gcc)	4m 17s
Compile sysdeps (aero)	2m 43s
Build mlibc (x86_64, mlibc-static, gcc)	3m 16s
Compile sysdeps (ironclad)	2m 20s
Build mlibc (x86_64, mlibc-shared, gcc)	3m 3s
Compile sysdeps (lyre)	2m 26s
Build mlibc (x86_64, mlibc-ansi-only, gcc)	2m 56s
Compile sysdeps (keyronex)	2m 28s
Build mlibc (x86_64, mlibc-headers-only, gcc)	2m 28s
Compile sysdeps (managarm)	2m 59s
Build mlibc (riscv64, mlibc, gcc)	3m 46s
Compile sysdeps (vinix)	2m 21s
Build mlibc (riscv64, mlibc-static, gcc)	4m 43s
Compile sysdeps (astral)	2m 30s
Build mlibc (riscv64, mlibc-shared, gcc)	3m 11s
Build mlibc (riscv64, mlibc-ansi-only, gcc)	2m 58s
Build mlibc (riscv64, mlibc-headers-only, gcc)	2m 8s
Build mlibc (aarch64, mlibc, gcc)	4m 20s
Build mlibc (aarch64, mlibc-static, gcc)	3m 41s
Build mlibc (aarch64, mlibc-shared, gcc)	3m 42s
Build mlibc (aarch64, mlibc-ansi-only, gcc)	3m 9s
Build mlibc (aarch64, mlibc-headers-only, gcc)	2m 3s
Build mlibc (x86, mlibc, gcc)	4m 2s
Build mlibc (x86, mlibc-static, gcc)	3m 14s
Build mlibc (x86, mlibc-shared, gcc)	3m 13s
Build mlibc (x86, mlibc-ansi-only, gcc)	3m 8s
Build mlibc (x86, mlibc-headers-only, gcc)	2m 4s
Build mlibc (m68k, mlibc, gcc)	3m 34s
Build mlibc (m68k, mlibc-static, gcc)	3m 5s
Build mlibc (m68k, mlibc-shared, gcc)	3m 15s
Build mlibc (m68k, mlibc-ansi-only, gcc)	2m 53s
Build mlibc (m68k, mlibc-headers-only, gcc)	2m 8s
Build mlibc (x86_64, mlibc, clang)	3m 16s
	1h 46m 34s

Provide feedback