diff --git a/lib/sig2str.h b/lib/sig2str.h
index 03d50c94317..1abdb140e5a 100644
--- a/lib/sig2str.h
+++ b/lib/sig2str.h
@@ -19,21 +19,6 @@
 
 #include <signal.h>
 
-/* Maximum size of a signal name returned by sig2str(), including the
-   terminating NUL byte.  */
-#ifndef SIG2STR_MAX
-/* The longest one: "RTMAX", then "+" or "-", then up to 10 digits, then NUL.
-   Add + 2 as a reserve for the future.  */
-# define SIG2STR_MAX (5 + 1 + 10 + 1 + 2)
-#endif
-
-#ifndef HAVE_SIG2STR
-int sig2str (int, char *);
-#endif
-#ifndef HAVE_STR2SIG
-int str2sig (char const *, int *);
-#endif
-
 /* An upper bound on signal numbers allowed by the system.  */
 
 #if defined _sys_nsig