Modernize k&r cairo-related function declarations.

Modernize k&r cairo-related function declarations.

* gtkutil.c (xg_page_setup_dialog, xg_get_page_setup, draw_page)
(xg_print_frames_dialog): Modernize k&r declarations.

* xfns.c (Fx_export_frames, Fx_page_setup_dialog, Fx_get_page_setup)
(Fx_print_frames_dialog): Modernize k&r declarations.

* xterm.c (x_gc_get_ext_data, x_extension_initialize, x_begin_cr_clip)
(x_end_cr_clip, x_set_cr_source_with_gc_foreground)
(x_set_cr_source_with_gc_background, x_cr_define_fringe_bitmap)
(x_cr_destroy_fringe_bitmap, x_cr_draw_frame, x_cr_accumulate_data)
(x_cr_destroy, x_cr_export_frames, x_prepare_for_xlibdraw)
(x_set_clip_rectangles, x_reset_clip_rectangles, x_fill_rectangle)
(x_draw_rectangle, x_clear_window, x_fill_trapezoid_for_relief)
(x_clear_area): Modernize k&r declarations.