'RELENG_5_3_0_RELEASE'.

This commit was manufactured to restore the state of the 5.3-RELEASE image.

item_add() should use safe_realloc() as it does no error checking itself.

o  Mount the EFI file system as msdosfs and not ufs as it's a FAT
   file system. Introduce Mount_msdos() for this to go side-by-side
   with Mount().
o  Also, since mounting is performed as a command (which means it's
   queued, sorted, lost, found and executed), we cannot create a
   directory on the file system by calling mkdir. We must make sure
   the mkdir happens after the mount. Introduce Mkdir_command() to
   allow mkdir operations to be queued, sorted, lost, found and
   executed as well.

Approved by: re (jhb, rwatson)

   Use static as necessary.
   Use __unused as necessary.
   sizeof(int) != sizeof(void *)

Suggested by:	bde

Submitted by:	bde