bug#13907: 24.3.50; cygw32 build mishandles drag-n-dropped file with non-ASCII characters in name

[Eli Zaretskii]

> Date: Fri, 08 Mar 2013 16:03:25 -0500
> From: Ken Brown <kbrown@cornell.edu>
> CC: Daniel Colascione <dancol@dancol.org>, 13907@debbugs.gnu.org
> 
> The value of file-name that is passed to 
> cygwin-convert-file-name-from-windows is "C:\\cygwin\\tmp\\\334.txt". 
> The converted file name is then "/tmp/ .txt".

The appearance of a blank (or a question mark) instead of a character
is usually a tell-tale sign of a botched character conversion.

For example, when I drag-n-drop into a native w32 Emacs a file name
that includes characters not from the system codepage, I get this:

  dnd-open-local-file: Can not read 
file:D%3A/gnu/ispell-3.3.02.w32/dictionaries/Tatar-Rus-%3Fngliz%20s%3Fzlege.htm

(%3F is the question mark.)