Various fixes and stubs to the glibc option for systemd #4210

Job	Run time
Build mlibc (x86_64, mlibc, gcc)	3m 58s
Build mlibc (x86_64, mlibc-static, gcc)	3m 27s
Compile sysdeps (dripos)	2m 19s
Build mlibc (x86_64, mlibc-shared, gcc)	3m 11s
Compile sysdeps (lemon)	2m 28s
Build mlibc (x86_64, mlibc-ansi-only, gcc)	3m 8s
Build mlibc (x86_64, mlibc-headers-only, gcc)	2m 9s
Compile sysdeps (aero)	2m 48s
Build mlibc (riscv64, mlibc, gcc)	3m 47s
Compile sysdeps (ironclad)	2m 52s
Build mlibc (riscv64, mlibc-static, gcc)	4m 46s
Compile sysdeps (lyre)	2m 17s
Compile sysdeps (keyronex)	2m 28s
Compile sysdeps (managarm)	2m 37s
Build mlibc (riscv64, mlibc-shared, gcc)	3m 8s
Compile sysdeps (vinix)	2m 17s
Compile sysdeps (astral)	2m 49s
Build mlibc (riscv64, mlibc-ansi-only, gcc)	3m 1s
Build mlibc (riscv64, mlibc-headers-only, gcc)	2m 6s
Build mlibc (aarch64, mlibc, gcc)	4m 8s
Build mlibc (aarch64, mlibc-static, gcc)	3m 19s
Build mlibc (aarch64, mlibc-shared, gcc)	3m 27s
Build mlibc (aarch64, mlibc-ansi-only, gcc)	3m 12s
Build mlibc (aarch64, mlibc-headers-only, gcc)	2m 5s
Build mlibc (x86, mlibc, gcc)	4m 8s
Build mlibc (x86, mlibc-static, gcc)	3m 25s
Build mlibc (x86, mlibc-shared, gcc)	3m 22s
Build mlibc (x86, mlibc-ansi-only, gcc)	3m 18s
Build mlibc (x86, mlibc-headers-only, gcc)	2m 46s
Build mlibc (m68k, mlibc, gcc)	3m 32s
Build mlibc (m68k, mlibc-static, gcc)	3m 5s
Build mlibc (m68k, mlibc-shared, gcc)	3m 2s
Build mlibc (m68k, mlibc-ansi-only, gcc)	2m 50s
Build mlibc (m68k, mlibc-headers-only, gcc)	2m 24s
Build mlibc (x86_64, mlibc, clang)	3m 24s
	1h 47m 3s

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