https://bugs.gentoo.org/944910
--- a/netcat.c
+++ b/netcat.c
@@ -257,7 +257,7 @@ void bail (str, p1, p2, p3, p4, p5, p6)
 
 /* catch :
    no-brainer interrupt handler */
-void catch ()
+void catch (__attribute__ ((unused)) int unused)
 {
   errno = 0;
   if (o_verbose > 1)		/* normally we don't care */
@@ -267,14 +267,14 @@ void catch ()
 
 /* quit :
    handler for a "-q" timeout (exit 0 instead of 1) */
-void quit ()
+void quit (__attribute__ ((unused)) int unused)
 {
   close (netfd);
   exit (0);
 }
 
 /* timeout and other signal handling cruft */
-void tmtravel ()
+void tmtravel (__attribute__ ((unused)) int unused)
 {
   signal (SIGALRM, SIG_IGN);
   alarm (0);