tools/nolibc: add support for getrlimit/setrlimit

The implementation uses the prlimit64 systemcall as that is available on
all architectures.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/20231123-nolibc-rlimit-v1-2-a428b131de2a@weissschuh.net/


Acked-by: Willy Tarreau <w@1wt.eu>