Fix initialization of the window-system variable.

Fix initialization of the window-system variable.

lisp/faces.el (x-create-frame-with-faces)
(tty-create-frame-with-faces): Don't set the window-system parameter
here, it seems to be unreliable.

lisp/frame.el (make-frame): Don't forget to return the new frame (d'oh).

src/frame.c (Qwindow_system): New symbol.
(syms_of_frame): Intern it.
(Fmake_terminal_frame): Initialize window-system frame parameter.

src/frame.h (Qwindow_system): New declaration.

src/xfns.c (Fx_create_frame, x_create_tip_frame): Initialize
window-system frame parameter.

git-archimport-id: lorentey@elte.hu--2004/emacs--multi-tty--0--patch-56