diff --git a/libc/include/machine/posix_limits.h b/libc/include/machine/posix_limits.h
index e5a299b..073d0df 100644
--- a/libc/include/machine/posix_limits.h
+++ b/libc/include/machine/posix_limits.h
@@ -69,7 +69,7 @@
 #define _POSIX_PRIORITIZED_IO       -1  /* not implemented */
 #define _POSIX_RAW_SOCKETS          200809L
 #define _POSIX_READER_WRITER_LOCKS  200809L
-#define _POSIX_REALTIME_SIGNALS     -1 /* for now, this is not supported */
+#define _POSIX_REALTIME_SIGNALS     200809L
 #define _POSIX_REGEXP               1
 #define _POSIX_RE_DUP_MAX           255
 #define _POSIX_SAVED_IDS            1  /* saved user ids is a Linux feature */
diff --git a/libc/include/signal.h b/libc/include/signal.h
index 6d89ef7..867f497 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -32,6 +32,7 @@
 #include <asm/sigcontext.h>
 #include <errno.h>
 #include <limits.h>
+#include <linux/time.h>
 #include <machine/pthread_types.h>
 #include <string.h>
 #include <sys/cdefs.h>
@@ -133,6 +134,10 @@
 extern int pthread_kill(pthread_t, int);
 extern int pthread_sigmask(int, const sigset_t*, sigset_t*);
 
+extern int sigqueue(pid_t, int, const union sigval);
+extern int sigtimedwait(const sigset_t*, siginfo_t*, const struct timespec*);
+extern int sigwaitinfo(const sigset_t*, siginfo_t*);
+
 __END_DECLS
 
 #endif /* _SIGNAL_H_ */