* fhandler.h (class fhandler_dev_clipboard): Remove member eof.

* fhandler_clipboard.cc: Throughout remove handling of eof member.
	(fhandler_dev_clipboard::write): Handle EOF condition immediately,
	rather than pushing it erroneously to the next read call.  Rearrange
	code.  Fix bug in CF_UNICODETEXT case which potentially dropped single
	bytes at the end of the buffer.  Add comment.
	* strfuncs.cc (sys_cp_wcstombs): Allow returning non-NUL-terminated
	buffer if dst != NULL and len == (size_t) -1.  Extend leading comment
	to explain what's returned in more detail.

winsup/cygwin/fhandler.h

@@ -1721,7 +1721,6 @@ class fhandler_dev_clipboard: public fhandler_base
   _off64_t pos;
   void *membuffer;
   size_t msize;
-  bool eof;
  public:
   fhandler_dev_clipboard ();
   int is_windows () { return 1; }