Make validate_value check for non-portable hexadecimal numbers > 0xffffffff

bin/FIJI/Settings.pm

@@ -591,6 +591,7 @@ sub validate_value {
             if ($orig !~ /^(0|(0[xX][[:xdigit:]]+))$/) {
                 return "$orig does not look like a natural hexadecimal number";
             }
+            return "$orig is too large" if (length($orig) > 2+8); # Hexadecimal numbers > 0xffffffff are non-portable
             ${$v_ref} = hex($orig);
 
             # Check for natural value range. Should never trigger due to the regex above.