Add simple session management support to Haiku

Add simple session management support to Haiku

* lisp/term/common-win.el (emacs-save-session-functions): Move
from x-win.el to common-win.el.
* lisp/term/haiku-win.el (haiku-save-session-reply)
(emacs-session-save, handle-save-session): New functions.
* lisp/term/x-win.el (emacs-save-session-functions): Delete.

* src/haiku_font_support.cc (font_style_to_flags):
* src/haiku_support.h (enum haiku_font_weight): Turn weight
macros into enum.
(struct haiku_font_pattern): Likewise.
(struct haiku_session_manager_reply): New struct.
* src/haiku_io.c (haiku_io_init): Create sm port.
* src/haiku_support.cc (QuitRequested): Wait for reply from sm
port.
* src/haikufns.c (Fhaiku_save_session_reply): New function.
(syms_of_haikufns): Define new subr.
* src/haikuterm.c (haiku_read_socket): Send session management
events.
(haiku_term_init): Check new port.