lp:705210 - Compiling with BUILD/compile-pentium64-debug fails

support building with -all-static (no dlopen and dlclose make few
related declarations unused or "statement have no effect") and -Werror

sql-common/client_plugin.c

@@ -50,7 +50,8 @@ struct st_client_plugin_int {
 static my_bool initialized= 0;
 static MEM_ROOT mem_root;
 
-static const char *plugin_declarations_sym= "_mysql_client_plugin_declaration_";
+static const char *plugin_declarations_sym __attribute__((unused)) =
+                                "_mysql_client_plugin_declaration_";
 static uint plugin_version[MYSQL_CLIENT_MAX_PLUGINS]=
 {
   0, /* these two are taken by Connector/C */
@@ -180,7 +181,7 @@ add_plugin(MYSQL *mysql, struct st_mysql_client_plugin *plugin, void *dlhandle,
     plugin->deinit();
 err1:
   if (dlhandle)
-    dlclose(dlhandle);
+    (void)dlclose(dlhandle);
   set_mysql_extended_error(mysql, CR_AUTH_PLUGIN_CANNOT_LOAD, unknown_sqlstate,
                            ER(CR_AUTH_PLUGIN_CANNOT_LOAD), plugin->name,
                            errmsg);
@@ -287,7 +288,7 @@ void mysql_client_plugin_deinit()
       if (p->plugin->deinit)
         p->plugin->deinit();
       if (p->dlhandle)
-        dlclose(p->dlhandle);
+        (void)dlclose(p->dlhandle);
     }
 
   bzero(&plugin_list, sizeof(plugin_list));
@@ -365,7 +366,7 @@ mysql_load_plugin_v(MYSQL *mysql, const char *name, int type,
   if (!(sym= dlsym(dlhandle, plugin_declarations_sym)))
   {
     errmsg= "not a plugin";
-    dlclose(dlhandle);
+    (void)dlclose(dlhandle);
     goto err;
   }
 

sql/sql_plugin_services.h

@@ -36,7 +36,7 @@ static struct thd_alloc_service_st thd_alloc_handler= {
   thd_make_lex_string
 };
 
-static struct st_service_ref list_of_services[]=
+static struct st_service_ref list_of_services[] __attribute__((unused)) =
 {
   { "my_snprintf_service", VERSION_my_snprintf, &my_snprintf_handler },
   { "thd_alloc_service",   VERSION_thd_alloc,   &thd_alloc_handler }