sysdeps: simplify entry point #4228

Job	Run time
Compile sysdeps (dripos)	2m 19s
Compile sysdeps (lemon)	2m 26s
Build mlibc (x86_64, mlibc, gcc)	4m 12s
Compile sysdeps (aero)	2m 53s
Build mlibc (x86_64, mlibc-static, gcc)	3m 16s
Compile sysdeps (ironclad)	2m 23s
Build mlibc (x86_64, mlibc-shared, gcc)	3m 16s
Compile sysdeps (lyre)	2m 43s
Build mlibc (x86_64, mlibc-ansi-only, gcc)	2m 57s
Compile sysdeps (keyronex)	2m 22s
Build mlibc (x86_64, mlibc-headers-only, gcc)	2m 7s
Compile sysdeps (managarm)	2m 40s
Build mlibc (riscv64, mlibc, gcc)	3m 45s
Compile sysdeps (vinix)	2m 23s
Build mlibc (riscv64, mlibc-static, gcc)	4m 42s
Compile sysdeps (astral)	2m 50s
Build mlibc (riscv64, mlibc-shared, gcc)	3m 3s
Build mlibc (riscv64, mlibc-ansi-only, gcc)	2m 49s
Build mlibc (riscv64, mlibc-headers-only, gcc)	2m 3s
Build mlibc (aarch64, mlibc, gcc)	4m 29s
Build mlibc (aarch64, mlibc-static, gcc)	3m 25s
Build mlibc (aarch64, mlibc-shared, gcc)	3m 20s
Build mlibc (aarch64, mlibc-ansi-only, gcc)	3m 8s
Build mlibc (aarch64, mlibc-headers-only, gcc)	2m 4s
Build mlibc (x86, mlibc, gcc)	3m 53s
Build mlibc (x86, mlibc-static, gcc)	3m 22s
Build mlibc (x86, mlibc-shared, gcc)	3m 13s
Build mlibc (x86, mlibc-ansi-only, gcc)	3m 9s
Build mlibc (x86, mlibc-headers-only, gcc)	2m 3s
Build mlibc (m68k, mlibc, gcc)	3m 38s
Build mlibc (m68k, mlibc-static, gcc)	2m 57s
Build mlibc (m68k, mlibc-shared, gcc)	3m 2s
Build mlibc (m68k, mlibc-ansi-only, gcc)	2m 47s
Build mlibc (m68k, mlibc-headers-only, gcc)	2m 1s
Build mlibc (x86_64, mlibc, clang)	3m 13s
	1h 44m 53s

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