* src/font.c (font_open_entity): Declare 'min_width' where it is
first set, and only if HAVE_WINDOW_SYSTEM.
* src/frame.c [!HAVE_WINDOW_SYSTEM] (decode_window_system_frame):
Define _Noreturn version to avoid "suggest attribute noreturn"
compiler warning.
(check_window_system): Declare as _Noreturn.
(Ficonify_frame):
(Fset_frame_position): Don’t declare and set 'f'.
* src/xdisp.c (handle_single_display_spec): Declare
'fringe_bitmap' only if HAVE_WINDOW_SYSTEM.
(append_space_for_newline): Declare 'g' where it is first set.
(Fmove_point_visually): Declare and set 'target_is_eol_p' only if
HAVE_WINDOW_SYSTEM.
(show_mouse_face): Declare and set 'f' and 'phys_cursor_on_p' only
if HAVE_WINDOW_SYSTEM.
(note_mode_line_or_margin_highlight):
(note_mouse_highlight): Declare and set 'cursor' and 'pointer'
only if HAVE_WINDOW_SYSTEM.
* src/xfaces.c (realize_default_face): Declare and set 'face' only
if HAVE_X_WINDOWS. Remove redundant #ifdef.