gentoo-overlay/sys-apps/kmscon/files/kmscon-SIGUNUSED.patch

diff -ur kmscon-8/src/pty.c kmscon-8.new/src/pty.c
--- kmscon-8/src/pty.c	2018-01-10 09:03:09.477962638 -0600
+++ kmscon-8.new/src/pty.c	2018-01-10 09:04:21.620658836 -0600
@@ -299,8 +299,10 @@
 	if (ret)
 		log_warn("cannot reset blocked signals: %m");
 
+	#ifdef SIGUNUSED
 	for (i = 1; i < SIGUNUSED; ++i)
 		signal(i, SIG_DFL);
+	#endif
 
 	ret = grantpt(master);
 	if (ret < 0) {