diff --git a/libc/include/sys/linux-unistd.h b/libc/include/sys/linux-unistd.h
index 12f7704..eb04011 100644
--- a/libc/include/sys/linux-unistd.h
+++ b/libc/include/sys/linux-unistd.h
@@ -141,6 +141,7 @@
 int              __rt_sigprocmask (int  how, const sigset_t *set, sigset_t *oset, size_t sigsetsize);
 int              __rt_sigtimedwait (const sigset_t *set, struct siginfo_t  *info, struct timespec_t  *timeout, size_t  sigset_size);
 int              sigpending (sigset_t *);
+int              __sigaction (int, const struct sigaction *, struct sigaction *);
 int              socket (int, int, int);
 int              socketpair (int, int, int, int*);
 int              bind (int, struct sockaddr *, int);