fix another ppoll issue (missing sigset_t size argument)

src/linux/ppoll.c

@@ -5,5 +5,5 @@
 int ppoll(struct pollfd *fds, nfds_t n, const struct timespec *to, const sigset_t *mask)
 {
 	return syscall_cp(SYS_ppoll, fds, n,
-		to ? (struct timespec []){*to} : 0, mask);
+		to ? (struct timespec []){*to} : 0, mask, __SYSCALL_SSLEN);
 }