musl/src/linux/fallocate.c

#define _GNU_SOURCE
#include <fcntl.h>
#include "syscall.h"

int fallocate(int fd, int mode, off_t base, off_t len)
{
	return syscall(SYS_fallocate, fd, mode, __SYSCALL_LL_E(base),
		__SYSCALL_LL_E(len));
}