sysdeps/managarm: Add sys_fstatfs #4215

Job	Run time
Compile sysdeps (dripos)	2m 20s
Build mlibc (x86_64, mlibc, gcc)	3m 47s
Compile sysdeps (lemon)	2m 21s
Compile sysdeps (aero)	2m 32s
Build mlibc (x86_64, mlibc-static, gcc)	3m 10s
Build mlibc (x86_64, mlibc-shared, gcc)	3m 6s
Compile sysdeps (ironclad)	2m 21s
Build mlibc (x86_64, mlibc-ansi-only, gcc)	3m 5s
Compile sysdeps (lyre)	2m 16s
Build mlibc (x86_64, mlibc-headers-only, gcc)	2m 4s
Compile sysdeps (keyronex)	2m 17s
Build mlibc (riscv64, mlibc, gcc)	3m 53s
Compile sysdeps (managarm)	2m 11s
Build mlibc (riscv64, mlibc-static, gcc)	4m 36s
Compile sysdeps (vinix)	2m 15s
Build mlibc (riscv64, mlibc-shared, gcc)	3m 39s
Compile sysdeps (astral)	2m 43s
Build mlibc (riscv64, mlibc-ansi-only, gcc)	3m 28s
Build mlibc (riscv64, mlibc-headers-only, gcc)	2m 4s
Build mlibc (aarch64, mlibc, gcc)	4m 10s
Build mlibc (aarch64, mlibc-static, gcc)	6m 37s
Build mlibc (aarch64, mlibc-shared, gcc)	3m 22s
Build mlibc (aarch64, mlibc-ansi-only, gcc)	3m 10s
Build mlibc (aarch64, mlibc-headers-only, gcc)	2m 24s
Build mlibc (x86, mlibc, gcc)	3m 45s
Build mlibc (x86, mlibc-static, gcc)	2m 58s
Build mlibc (x86, mlibc-shared, gcc)	3m 14s
Build mlibc (x86, mlibc-ansi-only, gcc)	2m 59s
Build mlibc (x86, mlibc-headers-only, gcc)	1m 56s
Build mlibc (m68k, mlibc, gcc)	3m 39s
Build mlibc (m68k, mlibc-static, gcc)	3m 3s
Build mlibc (m68k, mlibc-shared, gcc)	3m 36s
Build mlibc (m68k, mlibc-ansi-only, gcc)	2m 51s
Build mlibc (m68k, mlibc-headers-only, gcc)	2m 1s
Build mlibc (x86_64, mlibc, clang)	3m 10s
	1h 47m 3s

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