Compatibility: 2.0+
Expects: AH    3aH
DS:DX address of an ASCIIZ  string of a directory name
Returns: AX    error code if CF is set to CY
Info: Removes an existing directory, but only if it is empty.

DS:DX points to an ASCIIZ string in the form...
d:\path\dirname 0 
...which identifies the directory to remove.  It must not contain
wildcards .

If CF is set on return, and error code is in AX and the directory
was not deleted.

Notes:   The directory must be empty of files and directories, must not
be the current directory, and must be free of other constraints
(no DOS Join or Subst in effect, etc.)
  If drive and/or leading path are omitted, defaults are assumed.
  The maximum length of the ASCIIZ string is 64 bytes.

- -

DOS Fn 3aH: Delete a Directory -- RMDIR