misc: Remove C99+ style single line comments from headers #3992

Job	Run time
Build mlibc (x86_64, mlibc, gcc)	3m 36s
Build mlibc (x86_64, mlibc-static, gcc)	3m 7s
Compile sysdeps (dripos)	2m 10s
Build mlibc (x86_64, mlibc-shared, gcc)	2m 55s
Compile sysdeps (lemon)	2m 11s
Build mlibc (x86_64, mlibc-ansi-only, gcc)	2m 52s
Build mlibc (x86_64, mlibc-headers-only, gcc)	1m 59s
Compile sysdeps (aero)	2m 15s
Build mlibc (riscv64, mlibc, gcc)	3m 40s
Compile sysdeps (ironclad)	2m 16s
Build mlibc (riscv64, mlibc-static, gcc)	4m 22s
Compile sysdeps (lyre)	2m 31s
Build mlibc (riscv64, mlibc-shared, gcc)	2m 51s
Compile sysdeps (keyronex)	2m 11s
Build mlibc (riscv64, mlibc-ansi-only, gcc)	2m 49s
Compile sysdeps (managarm)	2m 30s
Build mlibc (riscv64, mlibc-headers-only, gcc)	1m 48s
Build mlibc (aarch64, mlibc, gcc)	3m 48s
Compile sysdeps (vinix)	2m 13s
Build mlibc (aarch64, mlibc-static, gcc)	3m 14s
Compile sysdeps (astral)	2m 19s
Build mlibc (aarch64, mlibc-shared, gcc)	3m 10s
Build mlibc (aarch64, mlibc-ansi-only, gcc)	3m 18s
Build mlibc (aarch64, mlibc-headers-only, gcc)	2m 17s
Build mlibc (x86, mlibc, gcc)	3m 50s
Build mlibc (x86, mlibc-static, gcc)	3m 14s
Build mlibc (x86, mlibc-shared, gcc)	2m 54s
Build mlibc (x86, mlibc-ansi-only, gcc)	2m 58s
Build mlibc (x86, mlibc-headers-only, gcc)	1m 54s
Build mlibc (x86_64, mlibc, clang)	3m 14s
	1h 24m 26s

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