* fhandler_clipboard.cc: new file

* fhandler_clipboard.cc: new file
* Makefile.in: include fhandler_clipboard.o in DLL_OFILES list.
* fhandler.h: add FH_CLIPBOARD to the devices enum.
(fhandler_dev_clipboard): new
* path.cc (windows_device_names): add "\\dev\\clipboard"
(get_device_number): check for "clipboard"
* dcrt0.cc: declare a few more functions from winuser.h
* dtable.cc (dtable::build_fhandler): check for FH_CLIPBOARD in
switch().