(struct KBOARD, MULTI_KBOARD, current_kboard, all_kboards,

(struct KBOARD, MULTI_KBOARD, current_kboard, all_kboards,
Lisp_Misc_Kboard_Objfwd, Lisp_Kboard_Objfwd, XKBOARD_OBJFWD, KBOARD_OBJFWDP,
GC_KBOARD_OBJFWDP, kboard_locked, the_only_kboard, DEFVAR_KBOARD): Renamed
from PERDISPLAY, MULTI_PERDISPLAY, current_perdisplay, all_perdisplays,
Lisp_Misc_Display_Objfwd, Lisp_Display_Objfwd, XDISPLAY_OBJFWD,
DISPLAY_OBJFWDP, GC_DISPLAY_OBJFWDP, display_locked, the_only_perdisplay,
DEFVAR_DISPLAY.  All uses changed.
(struct KBOARD): New member reference_count.
(initial_kboard): Declare this var.