Fix buffer size checking

Yes, this means we've re-introduced CVE-2005-3534. Sigh.
void myseek(int handle,off_t a) {
	if (lseek(handle, a, SEEK_SET) < 0) {
		err("Can not seek locally!\n");
	}
}

void myseek(int handle,off_t a) {
	if (lseek(handle, a, SEEK_SET) < 0) {
		err("Can not seek locally!\n");
	}
}
