When use warnings is on and there is a null value in the monitor data it causes warnings. So add skip if __git_main is not defined.

scripts/zmcamtool.pl.in

@@ -417,6 +417,7 @@ sub toPreset
     # ip addresses, ports, usernames, etc. with generic placeholders
     if (!$noregex) {
         foreach (@data) {
+            next if ! $_;
             s/\b(?:\d{1,3}\.){3}\d{1,3}\b/<ip-address>/; # ip address
             s/<ip-address>:(6553[0-5]|655[0-2]\d|65[0-4]\d\d|6[0-4]\d{3}|[1-5]\d{4}|[1-9]\d{0,3}|0)$/<ip-address>:<port>/; # tcpip port
             s/\/\/.*:.*@/\/\/<username>:<pwd>@/; # user & pwd preceding an ip address