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>

# stdint_h.m4 serial 8
dnl Copyright (C) 1997-2004, 2006, 2008, 2009 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.

dnl From Paul Eggert.

# Define HAVE_STDINT_H_WITH_UINTMAX if <stdint.h> exists,
# doesn't clash with <sys/types.h>, and declares uintmax_t.

AC_DEFUN([gl_AC_HEADER_STDINT_H],
[
  AC_CACHE_CHECK([for stdint.h], [gl_cv_header_stdint_h],
  [AC_TRY_COMPILE(
    [#include <sys/types.h>
#include <stdint.h>],
    [uintmax_t i = (uintmax_t) -1; return !i;],
    [gl_cv_header_stdint_h=yes],
    [gl_cv_header_stdint_h=no])])
  if test $gl_cv_header_stdint_h = yes; then
    AC_DEFINE_UNQUOTED([HAVE_STDINT_H_WITH_UINTMAX], [1],
      [Define if <stdint.h> exists, doesn't clash with <sys/types.h>,
       and declares uintmax_t. ])
  fi
])