Re: C backtraces for Emacs

[Paul Eggert]

I've checked in that change (trunk bzr 109765 and 109766)
and so the Windows builds probably need tweaking now
along the lines previously discussed.

One other thing I just now noticed -- the Windows substitute
for unistd.h may need something like this:

#define STDIN_FILENO 0
#define STDOUT_FILENO 1
#define STDERR_FILENO 2

if Windows doesn't already have the equivalent.  The backtrace
code uses STDERR_FILENO rather than fileno (stderr)
as it's better not to rely on stdio's data structures
after an assertion has failed.