--- wall.c	2017-01-26 10:33:46.747971568 +0000
+++ wall.c.new	2017-01-25 18:03:36.205228336 +0000
@@ -109,7 +109,7 @@
   }
 
   openlog("wall", LOG_PID, LOG_USER);
-  syslog(LOG_INFO, "wall: user %s broadcasted %d lines (%d chars)",
+  syslog(LOG_INFO, "wall: user %s broadcasted %d lines (%zu chars)",
 	whoami, i, strlen(buf));
   closelog();