merge

mysql-test/README.suites

@@ -32,6 +32,16 @@ files cannot. Special options are
  --timezone, --plugin-load, --result-file, --config-file-template,
  --default-time-zone, --force-restart
 
+In particular, all --plugin-load instances on the command line (on the
+combined command line, assembled from different .opt and combinations
+files) are merged into one. That is, if, say, test-master.opt file contains
+--plugin-load=aaa.so and suite.opt has --plugin-load=bbb.so that mysqld
+will get --plugin-load=aaa.so:bbb.so. Also, empty --plugin-load options are
+removed from the command line. Which means that one can safely specify
+--plugin-load=$AAA_SO and if aaa.so was not built (perhaps, the plugin was
+statically linked into the server), the .opt file will not result in the
+invalid command line option that can cause the server to refuse to start.
+
 ==========================
 A suite can have suite.pm file in the suitedir. It must declare a
 package that inherits from My::Suite.

sql/sql_plugin.cc

@@ -3446,8 +3446,7 @@ void my_print_help_inc_plugins(my_option *main_options, uint size)
     {
       p= *dynamic_element(&plugin_array, idx, struct st_plugin_int **);
 
-      if (!p->plugin->system_vars ||
-          !(opt= construct_help_options(&mem_root, p)))
+      if (!(opt= construct_help_options(&mem_root, p)))
         continue;
 
       /* Only options with a non-NULL comment are displayed in help text */