Backport into build-200906240007-5.1.34sp1

> ------------------------------------------------------------
> revno: 2852.1.15
> revision-id: davi.arnaut@sun.com-20090409152525-b4vnj9atidmjh0mf
> parent: luis.soares@sun.com-20090409113044-2072kufy5efeohpp
> committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
> branch nick: 43706-5.1
> timestamp: Thu 2009-04-09 12:25:25 -0300
> message:
>   Bug#43706: libmysqld segfaults when re-intialised
>   Bug#44091: libmysqld gets stuck waiting on mutex on initialization
>   
>   The problem was that libmysqld wasn't enforcing a certain
>   initialization and deinitialization order for the mysys
>   library. Another problem was that the global object used
>   for management of log event handlers (aka LOGGER) wasn't
>   being prepared for a possible reutilization.
>   
>   What leads to the hang/crash reported is that a failure
>   to load the language file triggers a double call of the
>   cleanup functions, causing an already destroyed mutex to
>   be used.
>   
>   The solution is enforce a order on the initialization and
>   deinitialization of the mysys library within the libmysqld
>   library and to ensure that the global LOGGER object reset
>   it's internal state during cleanup.

mysys/my_init.c

@@ -136,6 +136,10 @@ void my_end(int infoflag)
   */
   FILE *info_file= DBUG_FILE;
   my_bool print_info= (info_file != stderr);
+
+  if (!my_init_done)
+    return;
+
   /*
     We do not use DBUG_ENTER here, as after cleanup DBUG is no longer
     operational, so we cannot use DBUG_RETURN.

sql/log.cc

@@ -845,6 +845,7 @@ void LOGGER::cleanup_base()
   {
     table_log_handler->cleanup();
     delete table_log_handler;
+    table_log_handler= NULL;
   }
   if (file_log_handler)
     file_log_handler->cleanup();
@@ -855,7 +856,11 @@ void LOGGER::cleanup_end()
 {
   DBUG_ASSERT(inited == 1);
   if (file_log_handler)
+  {
     delete file_log_handler;
+    file_log_handler=NULL;
+  }
+  inited= 0;
 }