missing prototype for ioctl()

Index: plugins-root/check_icmp.c
--- plugins-root/check_icmp.c.orig
+++ plugins-root/check_icmp.c
@@ -52,6 +52,7 @@ const char *email = "devel@monitoring-plugins.org";
 #endif
 
 #include <sys/time.h>
+#include <sys/ioctl.h>
 #include <errno.h>
 #include <signal.h>
 #include <ctype.h>
