diff -Naur swaylock-1.8.3.orig/comm.c swaylock-1.8.3/comm.c
--- swaylock-1.8.3.orig/comm.c	2025-08-03 18:06:14.539816977 +0200
+++ swaylock-1.8.3/comm.c	2025-08-03 18:06:43.630190526 +0200
@@ -7,6 +7,7 @@
 #include "log.h"
 #include "swaylock.h"
 #include "password-buffer.h"
+#include "signal.h"
 
 static int comm[2][2] = {{-1, -1}, {-1, -1}};