bug#15878: 24.3.50; enhancement request: Add a working substitute for cygwin-mount.el to Emacs

[Drew Adams <drew.adams@oracle.com>]

From bug #15648, http://debbugs.gnu.org/cgi/bugreport.cgi?bug=15648#241,
Eli Zaretskii:

  Now, it might be possible to develop cygwin-mount to the degree that
  it does work reliably (which will most probably mean either
  introduction of much more hooks into Emacs to allow that, or
  reimplementation of many of the C portions in Lisp).

  If someone submits patches to do that, it would probably be a
  welcome addition to Emacs.  But we are not there yet.
  ^^^^^^^^^^^^^^^^^^^^^^^^^

That's the enhancement request: Give users what cygwin-mount.el gives
them, but cleanly, correctly, and completely, at least as far as
possible.  It seems that lots of Emacs users use cygwin-mount.el, but
Emacs has never offered support in this area. Here's hoping it will.
The decades have past, and we're still in the same place in this
regard.  Hope someone knowledgable will volunteer to DTRT.

In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-10-19 on LEG570
Bzr revision: 114715 rgm@gnu.org-20131019023520-s8mwtib7xcx9e05w
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking 'CFLAGS=-O0 -g3' CPPFLAGS=-DGLYPH_DEBUG=1'