Function: set-window-combination-limit

Set combination limit of window WINDOW to LIMIT; return LIMIT.
If LIMIT is nil, child windows of WINDOW can be recombined with WINDOW's
siblings. LIMIT t means that child windows of WINDOW are never
(re-)combined with WINDOW's siblings. Other values are reserved for
future use.

WINDOW must be a valid window. Setting the combination limit is
meaningful for internal windows only. (fn WINDOW LIMIT)