Compatibility:  WIN 3.0+
Expects: AX    1708H
Returns: AX    0000h = error
else  = success
Info: This releases control of the clipboard so that Windows
applications and other DOS apps can place data into it.
Equivalent to CloseClipboard.

In general, your clipboard access should take place all at once:
open it, access it, then close it.

- -

INT 2fH 1708H: Release Control of the Clipboard