Compatibility: 2.0+
Expects: AH    39H
DS:DX address of an ASCIIZ  string of a directory name
Returns: AX    error code if CF is set to CY
Info: Creates a new, empty directory.

DS:DX points to an ASCIIZ string in the form...
d:\path\dirname 0 
...which identifies the directory to create.

Notes:   A new directory can be created ONLY in an existing directory
(this fn will NOT create several directory levels at once).

  If drive and/or leading path are omitted, defaults are assumed.

  The maximum length of the ASCIIZ string is 64 bytes.

- -

DOS Fn 39H: Create a New Directory -- MKDIR