src/w32*.c: Clean up extern declarations.

src/w32*.c: Clean up extern declarations.

* w32select.c: Don't #include "keyboard.h".
  (run_protected): Add extern declaration for  waiting_for_input.

* lisp.h (VWindow_system, Qfile_name_history):
* keyboard.h (lispy_function_keys) [WINDOWSNT]:
* w32term.h (w32_system_caret_hwnd, w32_system_caret_height)
  (w32_system_caret_x, w32_system_caret_y): Declare extern.

* w32.c (Qlocal, noninteractive1, inhibit_window_system):
* w32console.c (detect_input_pending, read_input_pending)
  (encode_terminal_code):
* w32fns.c (quit_char, lispy_function_keys, Qtooltip)
  (w32_system_caret_hwnd, w32_system_caret_height, w32_system_caret_x)
  (w32_system_caret_y, Qfile_name_history):
* w32font.c (w32font_driver, QCantialias, QCotf, QClang):
* w32inevt.c (reinvoke_input_signal, lispy_function_keys):
* w32menu.c (Qmenu_bar, QCtoggle, QCradio, Qoverriding_local_map)
  (Qoverriding_terminal_local_map, Qmenu_bar_update_hook):
* w32proc.c (Qlocal, report_file_error):
* w32term.c (Vwindow_system, updating_frame):
* w32uniscribe.c (initialized, uniscribe_font_driver):
  Remove unneeded extern declarations.