various fixes for failing GMP tests #4302

Job	Run time
Compile sysdeps (dripos)	2m 48s
Compile sysdeps (lemon)	2m 22s
Build mlibc (x86_64, mlibc, gcc)	3m 3s
Compile sysdeps (aero)	2m 20s
Build mlibc (x86_64, mlibc-static, gcc)	30s
Build mlibc (x86_64, mlibc-shared, gcc)	40s
Compile sysdeps (ironclad)	2m 29s
Build mlibc (x86_64, mlibc-ansi-only, gcc)	2m 50s
Compile sysdeps (lyre)	2m 46s
Build mlibc (x86_64, mlibc-headers-only, gcc)	33s
Compile sysdeps (keyronex)	2m 47s
Build mlibc (riscv64, mlibc, gcc)	3m 4s
Compile sysdeps (managarm)	2m 39s
Build mlibc (riscv64, mlibc-static, gcc)	3m 2s
Compile sysdeps (vinix)	2m 21s
Build mlibc (riscv64, mlibc-shared, gcc)	3m 3s
Compile sysdeps (astral)	2m 25s
Build mlibc (riscv64, mlibc-ansi-only, gcc)	3m 4s
Build mlibc (riscv64, mlibc-headers-only, gcc)	2m 24s
Build mlibc (aarch64, mlibc, gcc)	3m 5s
Build mlibc (aarch64, mlibc-static, gcc)	3m 4s
Build mlibc (aarch64, mlibc-shared, gcc)	3m 6s
Build mlibc (aarch64, mlibc-ansi-only, gcc)	3m 5s
Build mlibc (aarch64, mlibc-headers-only, gcc)	2m 12s
Build mlibc (x86, mlibc, gcc)	12s
Build mlibc (x86, mlibc-static, gcc)	1s
Build mlibc (x86, mlibc-shared, gcc)	1s
Build mlibc (x86, mlibc-ansi-only, gcc)	1s
Build mlibc (x86, mlibc-headers-only, gcc)	1s
Build mlibc (m68k, mlibc, gcc)	3m 5s
Build mlibc (m68k, mlibc-static, gcc)	3m 3s
Build mlibc (m68k, mlibc-shared, gcc)	3m 5s
Build mlibc (m68k, mlibc-ansi-only, gcc)	2m 59s
Build mlibc (m68k, mlibc-headers-only, gcc)	2m 43s
Build mlibc (x86_64, mlibc, clang)	3m 4s
	1h 17m 57s

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