Several fixes revelaled by Intel compiler.

cmd-line-utils/readline/complete.c:
  Added a cast.
dbug/my_main.c:
  Added an include to avoid implicit declaration of
  my_thread_global_init()
include/my_global.h:
  undef cannot be used on this predefined name.
  Since it is a custom fix for gcc 2.8.0, let's make it only
  effective in that case.
include/my_sys.h:
  Added a new type, TYPE_NOT_SET.
myisam/ft_boolean_search.c:
  Added casts.
myisam/mi_key.c:
  Added cast.
myisam/mi_open.c:
  Added cast.
  Changed function types.
myisam/mi_test1.c:
  Added cast.
myisam/myisamchk.c:
  Added cast.
myisam/myisamdef.h:
  Changed function type.
myisam/myisampack.c:
  Added casts.
myisam/sp_key.c:
  Added cast.
mysys/mf_iocache.c:
  Fixed invalid use of 0 to info->type. According to comment it
  should not have been set, but in earlier code by setting it
  to 0 would have been same as setting it to READ_CACHE. This
  probably was not desired, potential bug.
server-tools/instance-manager/instance_options.cc:
  Fixed a typo.
server-tools/instance-manager/protocol.cc:
  Changed enum to int.
  Changed char to uchar.
  Added casts.
sql/mysql_priv.h:
  Bit overflow.
sql/sql_base.cc:
  Removed unused label. The code below label was unused too, because
  there is a return just before.
sql/sql_parse.cc:
  Removed unneccessary extra argument.

mysys/mf_iocache.c

@@ -165,7 +165,7 @@ int init_io_cache(IO_CACHE *info, File file, uint cachesize,
 		      (ulong) info, (int) type, (ulong) seek_offset));
 
   info->file= file;
-  info->type= 0;		/* Don't set it until mutex are created */
+  info->type= TYPE_NOT_SET;	    /* Don't set it until mutex are created */
   info->pos_in_file= seek_offset;
   info->pre_close = info->pre_read = info->post_read = 0;
   info->arg = 0;
@@ -1246,7 +1246,7 @@ int end_io_cache(IO_CACHE *info)
   if (info->type == SEQ_READ_APPEND)
   {
     /* Destroy allocated mutex */
-    info->type=0;
+    info->type= TYPE_NOT_SET;
 #ifdef THREAD
     pthread_mutex_destroy(&info->append_buffer_lock);
 #endif