Include file cleanup for w32 files in src directory

Include file cleanup for w32 files in src directory

* src/w32xfns.c: Don't include keyboard.h, window.h, charset.h,
fontset.h, blockinput.h.
* src/w32uniscribe.c: Don't include dispextern.h, character.h,
charset.h, fontset.h.
* src/w32term.c: Don't include systty.h, systime.h, charset.h,
character.h, ccl.h, dispextern.h, disptab.h, intervals.h,
process.h, atimer.h, keymap.h, w32heap.h.  Include bitmap/gray.xbm
in an ifdef-ed away block.
Include fcntl.h for CYGWIN.
(set_frame_param): Remove unused function.
* src/w32select.c: Don't include charset.h and composite.h.
(setup_config, Fw32_get_clipboard_data): Avoid compiler warnings
due to pointer signedness mismatches.
* src/w32reg.c (w32_get_string_resource): Avoid compiler warnings
due to pointer signedness mismatches.
* src/w32proc.c: Include unistd.h.  Don't include systime.h,
process.h, dispextern.h.
(sys_spawnve, Fw32_short_file_name, Fw32_long_file_name)
(Fw32_application_type): Avoid compiler warnings due to pointer
signedness mismatches.
* src/w32menu.c: Don't include keymap.h, termhooks.h, window.h,
character.h, charset.h, dispextern.h.
(simple_dialog_show, add_menu_item): Avoid compiler warnings due
to pointer signedness mismatches.
* src/w32inevt.c: Don't include dispextern.h, window.h,
termhooks.h, w32heap.h.
* src/w32font.c: Don't include dispextern.h, character.h,
charset.h, fontset.h, font.h.
(intern_font_name, add_font_entity_to_list)
(registry_to_w32_charset, w32_to_x_charset, fill_in_logfont)
(list_all_matching_fonts): Avoid compiler warnings due to pointer
signedness mismatches.
* src/w32fns.c: Don't include character.h, intervals.h,
dispextern.h, epaths.h, charset.h, ccl.h, fontset.h, systime.h,
termhooks.h, w32heap.h, bitmap/gray.xbm, font.h, w32font.h.
(w32_color_map_lookup, add_system_logical_colors_to_map)
(x_decode_color, x_set_name, FPRINTF_WM_CHARS, Fxw_color_defined_p)
(Fxw_color_values, x_display_info_for_name, Fset_message_beep)
(x_create_tip_frame, Fx_file_dialog, Fsystem_move_file_to_trash)
(w32_parse_hot_key, Ffile_system_info, w32_kbd_patch_key): Avoid
compiler warnings, mainly due to pointer signedness mismatches.
(unwind_create_frame_1): Remove unused function.
* src/w32console.c: Don't include character.h, disptab.h, frame.h,
window.h, termhooks.h, dispextern.h.
(w32con_write_glyphs, w32con_write_glyphs_with_face): Fix pointer
signedness mismatch.
* src/w32.c: Include c-strcase.h and systty.h.  Don't include
w32heap.h.