Fix unportable usage associated with va_list arguments.  Passing "0" to
a va_list argument only works if va_list is an integer or pointer type,
which is not required by the C spec, and is not true on ARM for instance.
Per bug #744707.


diff -up mysql-5.5.28/sql-common/client_plugin.c.p12 mysql-5.5.28/sql-common/client_plugin.c
--- mysql-5.5.28/sql-common/client_plugin.c.p12	2012-08-29 10:50:46.000000000 +0200
+++ mysql-5.5.28/sql-common/client_plugin.c	2012-12-06 14:22:54.494857607 +0100
@@ -233,11 +233,13 @@ int mysql_client_plugin_init()
 {
   MYSQL mysql;
   struct st_mysql_client_plugin **builtin;
+  va_list unused;
 
   if (initialized)
     return 0;
 
   bzero(&mysql, sizeof(mysql)); /* dummy mysql for set_mysql_extended_error */
+  bzero(&unused, sizeof(unused)); /* suppress uninitialized-value warnings */
 
   pthread_mutex_init(&LOCK_load_client_plugin, MY_MUTEX_INIT_SLOW);
   init_alloc_root(&mem_root, 128, 128);
@@ -249,7 +251,7 @@ int mysql_client_plugin_init()
   pthread_mutex_lock(&LOCK_load_client_plugin);
 
   for (builtin= mysql_client_builtins; *builtin; builtin++)
-    add_plugin(&mysql, *builtin, 0, 0, 0);
+    add_plugin(&mysql, *builtin, 0, 0, unused);
 
   pthread_mutex_unlock(&LOCK_load_client_plugin);
 
@@ -293,9 +295,13 @@ struct st_mysql_client_plugin *
 mysql_client_register_plugin(MYSQL *mysql,
                              struct st_mysql_client_plugin *plugin)
 {
+  va_list unused;
+
   if (is_not_initialized(mysql, plugin->name))
     return NULL;
 
+  bzero(&unused, sizeof(unused)); /* suppress uninitialized-value warnings */
+
   pthread_mutex_lock(&LOCK_load_client_plugin);
 
   /* make sure the plugin wasn't loaded meanwhile */
@@ -307,7 +313,7 @@ mysql_client_register_plugin(MYSQL *mysq
     plugin= NULL;
   }
   else
-    plugin= add_plugin(mysql, plugin, 0, 0, 0);
+    plugin= add_plugin(mysql, plugin, 0, 0, unused);
 
   pthread_mutex_unlock(&LOCK_load_client_plugin);
   return plugin;