Addendum to the fix for bug #12325444

Removed STDCALL from the function definition.

sql-common/client_plugin.c

@@ -460,7 +460,7 @@ mysql_client_find_plugin(MYSQL *mysql, const char *name, int type)
 
 
 /* see <mysql/client_plugin.h> for a full description */
-int STDCALL mysql_plugin_options(struct st_mysql_client_plugin *plugin,
+int mysql_plugin_options(struct st_mysql_client_plugin *plugin,
                                  const char *option,
                                  const void *value)
 {