diff -Naur mysql-5.5.57/client/mysql.cc mysql-5.5.57-gcc7/client/mysql.cc
--- mysql-5.5.57/client/mysql.cc	2017-06-05 08:38:02.000000000 +0200
+++ mysql-5.5.57-gcc7/client/mysql.cc	2017-08-02 16:09:20.854369133 +0200
@@ -2668,7 +2668,7 @@
         mysql_free_result(fields);
         break;
       }
-      field_names[i][num_fields*2]= '\0';
+      field_names[i][num_fields*2]= NULL;
       j=0;
       while ((sql_field=mysql_fetch_field(fields)))
       {