bug#20681: Build failure [MSYS2/MINGW64, OSX]

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 29 May 2015 21:57:47 +0200
> From: Andreas Grünbacher <andreas.gruenbacher@gmail.com>
> Cc: 20681-done@debbugs.gnu.org, Paul Eggert <eggert@cs.ucla.edu>,
> 	Angelo Graziosi <angelo.graziosi@alice.it>
> 
> 2015-05-29 21:56 GMT+02:00 Nick Andryshak <nandryshak@gmail.com>:
> > Thanks Paul and Andreas, this does indeed fix the build problem on
> > Cygwin.
> 
> Great, thanks.

Not sure if that code is supposed to be compatible with MinGW, but if
it is, there's still a problem, since set-permissions.c won't compile:

  set-permissions.c: In function 'set_acls':
  set-permissions.c:496:7: error: #error Must have acl_delete_def_file (see POSIX 1003.1e draft 17).
   #     error Must have acl_delete_def_file (see POSIX 1003.1e draft 17).
	 ^
  set-permissions.c:534:7: warning: implicit declaration of function 'acl_delete_def_file' [-Wimplicit-function-declaration]
	 ret = acl_delete_def_file (name);
	 ^
  Makefile:1563: recipe for target `set-permissions.o' failed

It's not a problem for Emacs, since the MinGW build doesn't compile
that file, but it means that other projects using gnulib might not
build on MinGW.

Thanks.