charset.c:

  he mysqld server crashes if issued a command select convert(...)
  with a
  non-compiled character set:

mysys/charset.c

@@ -539,8 +539,8 @@ static CHARSET_INFO *get_internal_charset(uint cs_number, myf flags)
   {
      strxmov(get_charsets_dir(buf), cs->csname, ".xml", NullS);
      my_read_charset_file(buf,flags);
-     cs= (cs->state & MY_CS_LOADED) ? cs : NULL;
   }
+  cs= (cs->state & MY_CS_AVAILABLE) ? cs : NULL;
   pthread_mutex_unlock(&THR_LOCK_charset);
   return cs;
 }