fcntl: support F_DUPFD_CLOEXEC on systems with fcntl Implement F_DUPFD_CLOEXEC. The unit test still fails on systems with other fcntl bugs (such as cygwin 1.5 mishandling F_DUPFD, or mingw lacking fcntl altogether). Passes on Linux, both with and without kernel support, and on cygwin 1.7. * modules/fcntl (Files): List new files. (configure.ac): Run a test. * m4/fcntl.m4 (gl_FUNC_FCNTL): New file. * lib/fcntl.c (rpl_fcntl): Likewise. * m4/fcntl_h.m4 (gl_FCNTL_H_DEFAULTS): Add witness defaults. (gl_FCNTL_H): Always replace fcntl.h. * modules/fcntl-h (Makefile.am): Substitute witnesses. * lib/fcntl.in.h (fcntl): Declare replacement. (F_DUPFD_CLOEXEC, GNULIB_defined_F_DUPFD_CLOEXEC): New macro when needed, plus a witness. * doc/posix-functions/fcntl.texi (fcntl): Document this. * doc/posix-headers/fcntl.texi (fcntl.h): Likewise. * tests/test-fcntl.c: New file. * modules/fcntl-tests: Likewise. Signed-off-by: Eric Blake <ebb9@byu.net>

#serial 16
dnl Copyright (C) 2005-2008 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_FTS],
[
  gl_FUNC_FTS_CORE
])

AC_DEFUN([gl_FUNC_FTS_LGPL],
[
  gl_FUNC_FTS_CORE
])

AC_DEFUN([gl_FUNC_FTS_CORE],
[
  dnl Use this version of fts unconditionally, since the GNU libc and
  dnl NetBSD versions have bugs and/or unnecessary limitations.
  AC_LIBOBJ([fts])

  dnl Prerequisites of lib/fts.c.
  gl_FUNC_OPENAT

  AC_CHECK_FUNCS_ONCE([fstatfs])
  AC_CHECK_HEADERS_ONCE([sys/param.h sys/vfs.h])dnl
  AC_CHECK_MEMBERS([struct statfs.f_type],,,
    [$ac_includes_default
     #include <sys/vfs.h>])
])