bug#11816: sort -o: error comes late if opening the outfile fails

[Jim Meyering]

Paul Eggert wrote:
> Thanks for the improvement.
> How about the following patch to simplify this a bit?
> It removes a call to fdopen, among other things.
>
>>From 05cc1b416a47330ef296dbeadd2a4b6095fe5c7d Mon Sep 17 00:00:00 2001
> From: Paul Eggert <address@hidden>
> Date: Mon, 2 Jul 2012 15:47:03 -0700
> Subject: [PATCH] sort: simplify -o handling to avoid fdopen, assert
>
> * src/sort.c (outfd): Remove.  All uses replaced by STDOUT_FILENO.
> (stream_open): When writing, use stdout rather than fdopen.
> (move_fd_or_die): Renamed from dup2_or_die, with the added functionality
> of closing its first argument.  All uses changed.
> (avoid_trashing_input): Special case for !outfile no longer needed.
> (check_output): Arrange for standard output to go to the file,
> rather than storing the fd in outfd.

Nice further improvement.
Thanks!