nl-unit-test/third_party/nlbuild-autotools/repo/tools/host/share/autoconf/autoconf/headers.m4

# This file is part of Autoconf.			-*- Autoconf -*-
# Checking for headers.
#
# Copyright (C) 1988, 1999, 2000, 2001, 2002, 2003, 2004, 2006, 2008,
# 2009, 2010 Free Software Foundation, Inc.

# This file is part of Autoconf.  This program is free
# software; you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the
# Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# Under Section 7 of GPL version 3, you are granted additional
# permissions described in the Autoconf Configure Script Exception,
# version 3.0, as published by the Free Software Foundation.
#
# You should have received a copy of the GNU General Public License
# and a copy of the Autoconf Configure Script Exception along with
# this program; see the files COPYINGv3 and COPYING.EXCEPTION
# respectively.  If not, see <http://www.gnu.org/licenses/>.

# Written by David MacKenzie, with help from
# Franc,ois Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
# Roland McGrath, Noah Friedman, david d zuhn, and many others.


# Table of contents
#
# 1. Generic tests for headers
# 2. Default includes
# 3. Headers to tests with AC_CHECK_HEADERS
# 4. Tests for specific headers


## ------------------------------ ##
## 1. Generic tests for headers.  ##
## ------------------------------ ##


# AC_CHECK_HEADER(HEADER-FILE,
#		  [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#		  [INCLUDES])
# ---------------------------------------------------------
# We are slowly moving to checking headers with the compiler instead
# of the preproc, so that we actually learn about the usability of a
# header instead of its mere presence.  But since users are used to
# the old semantics, they check for headers in random order and
# without providing prerequisite headers.  This macro implements the
# transition phase, and should be cleaned up latter to use compilation
# only.
#
# If INCLUDES is empty, then check both via the compiler and preproc.
# If the results are different, issue a warning, but keep the preproc
# result.
#
# If INCLUDES is `-', keep only the old semantics.
#
# If INCLUDES is specified and different from `-', then use the new
# semantics only.
#
# The m4_indir allows for fewer expansions of $@.
AC_DEFUN([AC_CHECK_HEADER],
[m4_indir(m4_case([$4],
		  [],  [[_AC_CHECK_HEADER_MONGREL]],
		  [-], [[_AC_CHECK_HEADER_PREPROC]],
		       [[_AC_CHECK_HEADER_COMPILE]]), $@)
])# AC_CHECK_HEADER


# _AC_CHECK_HEADER_MONGREL_BODY
# -----------------------------
# Shell function body for _AC_CHECK_HEADER_MONGREL
m4_define([_AC_CHECK_HEADER_MONGREL_BODY],
[  AS_LINENO_PUSH([$[]1])
  AS_VAR_SET_IF([$[]3],
		[AC_CACHE_CHECK([for $[]2], [$[]3], [])],
		[# Is the header compilable?
AC_MSG_CHECKING([$[]2 usability])
AC_COMPILE_IFELSE([AC_LANG_SOURCE([$[]4
@%:@include <$[]2>])],
		  [ac_header_compiler=yes],
		  [ac_header_compiler=no])
AC_MSG_RESULT([$ac_header_compiler])

# Is the header present?
AC_MSG_CHECKING([$[]2 presence])
AC_PREPROC_IFELSE([AC_LANG_SOURCE([@%:@include <$[]2>])],
		  [ac_header_preproc=yes],
		  [ac_header_preproc=no])
AC_MSG_RESULT([$ac_header_preproc])

# So?  What about this header?
case $ac_header_compiler:$ac_header_preproc:$ac_[]_AC_LANG_ABBREV[]_preproc_warn_flag in #((
  yes:no: )
    AC_MSG_WARN([$[]2: accepted by the compiler, rejected by the preprocessor!])
    AC_MSG_WARN([$[]2: proceeding with the compiler's result])
    ;;
  no:yes:* )
    AC_MSG_WARN([$[]2: present but cannot be compiled])
    AC_MSG_WARN([$[]2:     check for missing prerequisite headers?])
    AC_MSG_WARN([$[]2: see the Autoconf documentation])
    AC_MSG_WARN([$[]2:     section "Present But Cannot Be Compiled"])
    AC_MSG_WARN([$[]2: proceeding with the compiler's result])
m4_ifset([AC_PACKAGE_BUGREPORT],
[m4_n([( AS_BOX([Report this to ]AC_PACKAGE_BUGREPORT)
     ) | sed "s/^/$as_me: WARNING:     /" >&2])])dnl
    ;;
esac
  AC_CACHE_CHECK([for $[]2], [$[]3],
		 [AS_VAR_SET([$[]3], [$ac_header_compiler])])])
  AS_LINENO_POP
])#_AC_CHECK_HEADER_MONGREL_BODY

# _AC_CHECK_HEADER_MONGREL(HEADER-FILE,
#			   [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#			   [INCLUDES = DEFAULT-INCLUDES])
# ------------------------------------------------------------------
# Check using both the compiler and the preprocessor.  If they disagree,
# warn, and the preproc wins.
#
# This is not based on _AC_CHECK_HEADER_COMPILE and _AC_CHECK_HEADER_PREPROC
# because it obfuscate the code to try to factor everything, in particular
# because of the cache variables, and the `checking ...' messages.
AC_DEFUN([_AC_CHECK_HEADER_MONGREL],
[AC_REQUIRE_SHELL_FN([ac_fn_]_AC_LANG_ABBREV[_check_header_mongrel],
  [AS_FUNCTION_DESCRIBE([ac_fn_]_AC_LANG_ABBREV[_check_header_mongrel],
    [LINENO HEADER VAR INCLUDES],
    [Tests whether HEADER exists, giving a warning if it cannot be compiled
     using the include files in INCLUDES and setting the cache variable VAR
     accordingly.])],
  [$0_BODY])]dnl
[AS_VAR_PUSHDEF([ac_Header], [ac_cv_header_$1])]dnl
[ac_fn_[]_AC_LANG_ABBREV[]_check_header_mongrel ]dnl
["$LINENO" "$1" "ac_Header" "AS_ESCAPE([AC_INCLUDES_DEFAULT([$4])], [""])"
AS_VAR_IF([ac_Header], [yes], [$2], [$3])
AS_VAR_POPDEF([ac_Header])])# _AC_CHECK_HEADER_MONGREL


# _AC_CHECK_HEADER_COMPILE_BODY
# -----------------------------
# Shell function body for _AC_CHECK_HEADER_COMPILE
m4_define([_AC_CHECK_HEADER_COMPILE_BODY],
[  AS_LINENO_PUSH([$[]1])
  AC_CACHE_CHECK([for $[]2], [$[]3],
		 [AC_COMPILE_IFELSE([AC_LANG_SOURCE([$[]4
@%:@include <$[]2>])],
				    [AS_VAR_SET([$[]3], [yes])],
				    [AS_VAR_SET([$[]3], [no])])])
  AS_LINENO_POP
])# _AC_CHECK_HEADER_COMPILE_BODY

# _AC_CHECK_HEADER_COMPILE(HEADER-FILE,
#		       [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#		       [INCLUDES = DEFAULT-INCLUDES])
# --------------------------------------------------------------
# Check the compiler accepts HEADER-FILE.  The INCLUDES are defaulted.
AC_DEFUN([_AC_CHECK_HEADER_COMPILE],
[AC_REQUIRE_SHELL_FN([ac_fn_]_AC_LANG_ABBREV[_check_header_compile],
  [AS_FUNCTION_DESCRIBE([ac_fn_]_AC_LANG_ABBREV[_check_header_compile],
    [LINENO HEADER VAR INCLUDES],
    [Tests whether HEADER exists and can be compiled using the include files
     in INCLUDES, setting the cache variable VAR accordingly.])],
  [$0_BODY])]dnl
[AS_VAR_PUSHDEF([ac_Header], [ac_cv_header_$1])]dnl
[ac_fn_[]_AC_LANG_ABBREV[]_check_header_compile ]dnl
["$LINENO" "$1" "ac_Header" "AS_ESCAPE([AC_INCLUDES_DEFAULT([$4])], [""])"
AS_VAR_IF([ac_Header], [yes], [$2], [$3])
AS_VAR_POPDEF([ac_Header])])# _AC_CHECK_HEADER_COMPILE

# _AC_CHECK_HEADER_PREPROC_BODY
# -----------------------------
# Shell function body for _AC_CHECK_HEADER_PREPROC.
m4_define([_AC_CHECK_HEADER_PREPROC_BODY],
[  AS_LINENO_PUSH([$[]1])
  AC_CACHE_CHECK([for $[]2], [$[]3],
  [AC_PREPROC_IFELSE([AC_LANG_SOURCE([@%:@include <$[]2>])],
		     [AS_VAR_SET([$[]3], [yes])],
		     [AS_VAR_SET([$[]3], [no])])])
  AS_LINENO_POP
])# _AC_CHECK_HEADER_PREPROC_BODY



# _AC_CHECK_HEADER_PREPROC(HEADER-FILE,
#		       [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
# --------------------------------------------------------------
# Check the preprocessor accepts HEADER-FILE.
AC_DEFUN([_AC_CHECK_HEADER_PREPROC],
[AC_REQUIRE_SHELL_FN([ac_fn_]_AC_LANG_ABBREV[_check_header_preproc],
  [AS_FUNCTION_DESCRIBE([ac_fn_]_AC_LANG_ABBREV[_check_header_preproc],
    [LINENO HEADER VAR],
    [Tests whether HEADER is present, setting the cache variable VAR accordingly.])],
  [$0_BODY])]dnl
[AS_VAR_PUSHDEF([ac_Header], [ac_cv_header_$1])]dnl
[ac_fn_[]_AC_LANG_ABBREV[]_check_header_preproc "$LINENO" "$1" "ac_Header"
AS_VAR_IF([ac_Header], [yes], [$2], [$3])
AS_VAR_POPDEF([ac_Header])dnl
])# _AC_CHECK_HEADER_PREPROC

# _AC_CHECK_HEADER_OLD(HEADER-FILE, [ACTION-IF-FOUND],
#                      [ACTION-IF-NOT-FOUND])
# _AC_CHECK_HEADER_NEW(HEADER-FILE, [ACTION-IF-FOUND],
#                      [ACTION-IF-NOT-FOUND])
# ----------------------------------------------------
# Some packages used these undocumented macros.  Even worse, gcc
# redefined AC_CHECK_HEADER in terms of _AC_CHECK_HEADER_OLD, so we
# can't do the simpler:
#   AU_DEFUN([_AC_CHECK_HEADER_OLD],
#     [AC_CHECK_HEADER([$1], [$2], [$3], [-])])
AC_DEFUN([_AC_CHECK_HEADER_OLD],
[AC_DIAGNOSE([obsolete], [The macro `$0' is obsolete.
You should use AC_CHECK_HEADER with a fourth argument.])]dnl
[_AC_CHECK_HEADER_PREPROC($@)])

AC_DEFUN([_AC_CHECK_HEADER_NEW],
[AC_DIAGNOSE([obsolete], [The macro `$0' is obsolete.
You should use AC_CHECK_HEADER with a fourth argument.])]dnl
[_AC_CHECK_HEADER_COMPILE($@)])


# _AH_CHECK_HEADER(HEADER-FILE)
# -----------------------------
# Prepare the autoheader snippet for HEADER-FILE.
m4_define([_AH_CHECK_HEADER],
[AH_TEMPLATE(AS_TR_CPP([HAVE_$1]),
  [Define to 1 if you have the <$1> header file.])])


# AH_CHECK_HEADERS(HEADER-FILE...)
# --------------------------------
m4_define([AH_CHECK_HEADERS],
[m4_foreach_w([AC_Header], [$1], [_AH_CHECK_HEADER(m4_defn([AC_Header]))])])


# AC_CHECK_HEADERS(HEADER-FILE...,
#		   [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#		   [INCLUDES])
# ----------------------------------------------------------
# Check for each whitespace-separated HEADER-FILE (omitting the <> or
# ""), and perform ACTION-IF-FOUND or ACTION-IF-NOT-FOUND for each
# header.  INCLUDES is as for AC_CHECK_HEADER.  Additionally, make the
# preprocessor definition HAVE_HEADER_FILE available for each found
# header.  Either ACTION may include `break' to stop the search.
AC_DEFUN([AC_CHECK_HEADERS],
[m4_map_args_w([$1], [_AH_CHECK_HEADER(], [)])]dnl
[AS_FOR([AC_header], [ac_header], [$1],
[AC_CHECK_HEADER(AC_header,
		 [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_]AC_header)) $2],
		 [$3], [$4])dnl])
])# AC_CHECK_HEADERS


# _AC_CHECK_HEADER_ONCE(HEADER-FILE)
# ----------------------------------
# Check for a single HEADER-FILE once.
m4_define([_AC_CHECK_HEADER_ONCE],
[_AH_CHECK_HEADER([$1])AC_DEFUN([_AC_Header_]m4_translit([[$1]],
    [./-], [___]),
  [m4_divert_text([INIT_PREPARE], [AS_VAR_APPEND([ac_header_list], [" $1"])])
_AC_HEADERS_EXPANSION])AC_REQUIRE([_AC_Header_]m4_translit([[$1]],
    [./-], [___]))])


# AC_CHECK_HEADERS_ONCE(HEADER-FILE...)
# -------------------------------------
# Add each whitespace-separated name in HEADER-FILE to the list of
# headers to check once.
AC_DEFUN([AC_CHECK_HEADERS_ONCE],
[m4_map_args_w([$1], [_AC_CHECK_HEADER_ONCE(], [)])])

m4_define([_AC_HEADERS_EXPANSION],
[
  m4_divert_text([DEFAULTS], [ac_header_list=])
  AC_CHECK_HEADERS([$ac_header_list], [], [], [AC_INCLUDES_DEFAULT])
  m4_define([_AC_HEADERS_EXPANSION], [])
])




## --------------------- ##
## 2. Default includes.  ##
## --------------------- ##

# Always use the same set of default headers for all the generic
# macros.  It is easier to document, to extend, and to understand than
# having specific defaults for each macro.

# _AC_INCLUDES_DEFAULT_REQUIREMENTS
# ---------------------------------
# Required when AC_INCLUDES_DEFAULT uses its default branch.
AC_DEFUN([_AC_INCLUDES_DEFAULT_REQUIREMENTS],
[m4_divert_text([DEFAULTS],
[# Factoring default headers for most tests.
dnl If ever you change this variable, please keep autoconf.texi in sync.
ac_includes_default="\
#include <stdio.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
#  include <stdlib.h>
# endif
#endif
#ifdef HAVE_STRING_H
# if !defined STDC_HEADERS && defined HAVE_MEMORY_H
#  include <memory.h>
# endif
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif
#ifdef HAVE_INTTYPES_H
# include <inttypes.h>
#endif
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif"
])dnl
AC_REQUIRE([AC_HEADER_STDC])dnl
# On IRIX 5.3, sys/types and inttypes.h are conflicting.
AC_CHECK_HEADERS([sys/types.h sys/stat.h stdlib.h string.h memory.h strings.h \
		  inttypes.h stdint.h unistd.h],
		 [], [], $ac_includes_default)
])# _AC_INCLUDES_DEFAULT_REQUIREMENTS


# AC_INCLUDES_DEFAULT([INCLUDES])
# -------------------------------
# If INCLUDES is empty, expand in default includes, otherwise in
# INCLUDES.
# In most cases INCLUDES is not double quoted as it should, and if
# for instance INCLUDES = `#include <stdio.h>' then unless we force
# a newline, the hash will swallow the closing paren etc. etc.
# The usual failure.
# Take no risk: for the newline.
AC_DEFUN([AC_INCLUDES_DEFAULT],
[m4_ifval([$1], [$1
],
	  [AC_REQUIRE([_AC_INCLUDES_DEFAULT_REQUIREMENTS])dnl
$ac_includes_default])])





## ------------------------------------------- ##
## 3. Headers to check with AC_CHECK_HEADERS.  ##
## ------------------------------------------- ##

# errno.h is portable.

AN_HEADER([OS.h],               [AC_CHECK_HEADERS])
AN_HEADER([argz.h],             [AC_CHECK_HEADERS])
AN_HEADER([arpa/inet.h],        [AC_CHECK_HEADERS])
AN_HEADER([fcntl.h],            [AC_CHECK_HEADERS])
AN_HEADER([fenv.h],             [AC_CHECK_HEADERS])
AN_HEADER([float.h],            [AC_CHECK_HEADERS])
AN_HEADER([fs_info.h],          [AC_CHECK_HEADERS])
AN_HEADER([inttypes.h],         [AC_CHECK_HEADERS])
AN_HEADER([langinfo.h],         [AC_CHECK_HEADERS])
AN_HEADER([libintl.h],          [AC_CHECK_HEADERS])
AN_HEADER([limits.h],           [AC_CHECK_HEADERS])
AN_HEADER([locale.h],           [AC_CHECK_HEADERS])
AN_HEADER([mach/mach.h],        [AC_CHECK_HEADERS])
AN_HEADER([malloc.h],           [AC_CHECK_HEADERS])
AN_HEADER([memory.h],           [AC_CHECK_HEADERS])
AN_HEADER([mntent.h],           [AC_CHECK_HEADERS])
AN_HEADER([mnttab.h],           [AC_CHECK_HEADERS])
AN_HEADER([netdb.h],            [AC_CHECK_HEADERS])
AN_HEADER([netinet/in.h],       [AC_CHECK_HEADERS])
AN_HEADER([nl_types.h],         [AC_CHECK_HEADERS])
AN_HEADER([nlist.h],            [AC_CHECK_HEADERS])
AN_HEADER([paths.h],            [AC_CHECK_HEADERS])
AN_HEADER([sgtty.h],            [AC_CHECK_HEADERS])
AN_HEADER([shadow.h],           [AC_CHECK_HEADERS])
AN_HEADER([stddef.h],           [AC_CHECK_HEADERS])
AN_HEADER([stdint.h],           [AC_CHECK_HEADERS])
AN_HEADER([stdio_ext.h],        [AC_CHECK_HEADERS])
AN_HEADER([stdlib.h],           [AC_CHECK_HEADERS])
AN_HEADER([string.h],           [AC_CHECK_HEADERS])
AN_HEADER([strings.h],          [AC_CHECK_HEADERS])
AN_HEADER([sys/acl.h],          [AC_CHECK_HEADERS])
AN_HEADER([sys/file.h],         [AC_CHECK_HEADERS])
AN_HEADER([sys/filsys.h],       [AC_CHECK_HEADERS])
AN_HEADER([sys/fs/s5param.h],   [AC_CHECK_HEADERS])
AN_HEADER([sys/fs_types.h],     [AC_CHECK_HEADERS])
AN_HEADER([sys/fstyp.h],        [AC_CHECK_HEADERS])
AN_HEADER([sys/ioctl.h],        [AC_CHECK_HEADERS])
AN_HEADER([sys/mntent.h],       [AC_CHECK_HEADERS])
AN_HEADER([sys/mount.h],        [AC_CHECK_HEADERS])
AN_HEADER([sys/param.h],        [AC_CHECK_HEADERS])
AN_HEADER([sys/socket.h],       [AC_CHECK_HEADERS])
AN_HEADER([sys/statfs.h],       [AC_CHECK_HEADERS])
AN_HEADER([sys/statvfs.h],      [AC_CHECK_HEADERS])
AN_HEADER([sys/systeminfo.h],   [AC_CHECK_HEADERS])
AN_HEADER([sys/time.h],         [AC_CHECK_HEADERS])
AN_HEADER([sys/timeb.h],        [AC_CHECK_HEADERS])
AN_HEADER([sys/vfs.h],          [AC_CHECK_HEADERS])
AN_HEADER([sys/window.h],       [AC_CHECK_HEADERS])
AN_HEADER([syslog.h],           [AC_CHECK_HEADERS])
AN_HEADER([termio.h],           [AC_CHECK_HEADERS])
AN_HEADER([termios.h],          [AC_CHECK_HEADERS])
AN_HEADER([unistd.h],           [AC_CHECK_HEADERS])
AN_HEADER([utime.h],            [AC_CHECK_HEADERS])
AN_HEADER([utmp.h],             [AC_CHECK_HEADERS])
AN_HEADER([utmpx.h],            [AC_CHECK_HEADERS])
AN_HEADER([values.h],           [AC_CHECK_HEADERS])
AN_HEADER([wchar.h],            [AC_CHECK_HEADERS])
AN_HEADER([wctype.h],           [AC_CHECK_HEADERS])



## ------------------------------- ##
## 4. Tests for specific headers.  ##
## ------------------------------- ##

# AC_HEADER_ASSERT
# ----------------
# Check whether to enable assertions.
AC_DEFUN_ONCE([AC_HEADER_ASSERT],
[
  AC_MSG_CHECKING([whether to enable assertions])
  AC_ARG_ENABLE([assert],
    [AS_HELP_STRING([--disable-assert], [turn off assertions])],
    [ac_enable_assert=$enableval
     AS_IF(dnl
      [test "x$enableval" = xno],
	[AC_DEFINE([NDEBUG], [1],
	  [Define to 1 if assertions should be disabled.])],
      [test "x$enableval" != xyes],
	[AC_MSG_WARN([invalid argument supplied to --enable-assert])
	ac_enable_assert=yes])],
    [ac_enable_assert=yes])
  AC_MSG_RESULT([$ac_enable_assert])
])


# _AC_CHECK_HEADER_DIRENT(HEADER-FILE,
#			  [ACTION-IF-FOUND], [ACTION-IF-NOT_FOUND])
# -----------------------------------------------------------------
# Like AC_CHECK_HEADER, except also make sure that HEADER-FILE
# defines the type `DIR'.  dirent.h on NextStep 3.2 doesn't.
m4_define([_AC_CHECK_HEADER_DIRENT],
[AS_VAR_PUSHDEF([ac_Header], [ac_cv_header_dirent_$1])dnl
AC_CACHE_CHECK([for $1 that defines DIR], [ac_Header],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <sys/types.h>
#include <$1>
],
				    [if ((DIR *) 0)
return 0;])],
		   [AS_VAR_SET([ac_Header], [yes])],
		   [AS_VAR_SET([ac_Header], [no])])])
AS_VAR_IF([ac_Header], [yes], [$2], [$3])
AS_VAR_POPDEF([ac_Header])dnl
])# _AC_CHECK_HEADER_DIRENT


# _AH_CHECK_HEADER_DIRENT(HEADERS)
# --------------------------------
# Like _AH_CHECK_HEADER, but tuned to a dirent provider.
m4_define([_AH_CHECK_HEADER_DIRENT],
[AH_TEMPLATE(AS_TR_CPP([HAVE_$1]),
  [Define to 1 if you have the <$1> header file, and it defines `DIR'.])])


# AC_HEADER_DIRENT
# ----------------
AC_DEFUN([AC_HEADER_DIRENT],
[m4_map_args([_AH_CHECK_HEADER_DIRENT], [dirent.h], [sys/ndir.h],
	     [sys/dir.h], [ndir.h])]dnl
[ac_header_dirent=no
for ac_hdr in dirent.h sys/ndir.h sys/dir.h ndir.h; do
  _AC_CHECK_HEADER_DIRENT($ac_hdr,
			  [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_$ac_hdr), 1)
ac_header_dirent=$ac_hdr; break])
done
# Two versions of opendir et al. are in -ldir and -lx on SCO Xenix.
if test $ac_header_dirent = dirent.h; then
  AC_SEARCH_LIBS(opendir, dir)
else
  AC_SEARCH_LIBS(opendir, x)
fi
])# AC_HEADER_DIRENT


# AC_HEADER_MAJOR
# ---------------
AN_FUNCTION([major],     [AC_HEADER_MAJOR])
AN_FUNCTION([makedev],   [AC_HEADER_MAJOR])
AN_FUNCTION([minor],     [AC_HEADER_MAJOR])
AN_HEADER([sys/mkdev.h], [AC_HEADER_MAJOR])
AC_DEFUN([AC_HEADER_MAJOR],
[AC_CACHE_CHECK(whether sys/types.h defines makedev,
		ac_cv_header_sys_types_h_makedev,
[AC_LINK_IFELSE([AC_LANG_PROGRAM([[@%:@include <sys/types.h>]],
				 [[return makedev(0, 0);]])],
		[ac_cv_header_sys_types_h_makedev=yes],
		[ac_cv_header_sys_types_h_makedev=no])
])

if test $ac_cv_header_sys_types_h_makedev = no; then
AC_CHECK_HEADER(sys/mkdev.h,
		[AC_DEFINE(MAJOR_IN_MKDEV, 1,
			   [Define to 1 if `major', `minor', and `makedev' are
			    declared in <mkdev.h>.])])

  if test $ac_cv_header_sys_mkdev_h = no; then
    AC_CHECK_HEADER(sys/sysmacros.h,
		    [AC_DEFINE(MAJOR_IN_SYSMACROS, 1,
			       [Define to 1 if `major', `minor', and `makedev'
				are declared in <sysmacros.h>.])])
  fi
fi
])# AC_HEADER_MAJOR


# AC_HEADER_RESOLV
# ----------------
# According to http://www.mcsr.olemiss.edu/cgi-bin/man-cgi?resolver+3
# (or http://www.chemie.fu-berlin.de/cgi-bin/man/sgi_irix?resolver+3),
# sys/types.h, netinet/in.h and arpa/nameser.h are required on IRIX.
# netinet/in.h is needed on Cygwin, too.
# With Solaris 9, netdb.h is required, to get symbols like HOST_NOT_FOUND.
#
AN_HEADER(resolv.h,	[AC_HEADER_RESOLV])
AC_DEFUN([AC_HEADER_RESOLV],
[AC_CHECK_HEADERS(sys/types.h netinet/in.h arpa/nameser.h netdb.h resolv.h,
		  [], [],
[[#ifdef HAVE_SYS_TYPES_H
#  include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
#  include <netinet/in.h>   /* inet_ functions / structs */
#endif
#ifdef HAVE_ARPA_NAMESER_H
#  include <arpa/nameser.h> /* DNS HEADER struct */
#endif
#ifdef HAVE_NETDB_H
#  include <netdb.h>
#endif]])
])# AC_HEADER_RESOLV


# AC_HEADER_STAT
# --------------
# FIXME: Shouldn't this be named AC_HEADER_SYS_STAT?
AC_DEFUN([AC_HEADER_STAT],
[AC_CACHE_CHECK(whether stat file-mode macros are broken,
  ac_cv_header_stat_broken,
[AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#include <sys/types.h>
#include <sys/stat.h>

#if defined S_ISBLK && defined S_IFDIR
extern char c1[S_ISBLK (S_IFDIR) ? -1 : 1];
#endif

#if defined S_ISBLK && defined S_IFCHR
extern char c2[S_ISBLK (S_IFCHR) ? -1 : 1];
#endif

#if defined S_ISLNK && defined S_IFREG
extern char c3[S_ISLNK (S_IFREG) ? -1 : 1];
#endif

#if defined S_ISSOCK && defined S_IFREG
extern char c4[S_ISSOCK (S_IFREG) ? -1 : 1];
#endif
]])], ac_cv_header_stat_broken=no, ac_cv_header_stat_broken=yes)])
if test $ac_cv_header_stat_broken = yes; then
  AC_DEFINE(STAT_MACROS_BROKEN, 1,
	    [Define to 1 if the `S_IS*' macros in <sys/stat.h> do not
	     work properly.])
fi
])# AC_HEADER_STAT


# AC_HEADER_STDBOOL
# -----------------
# Check for stdbool.h that conforms to C99.
AN_IDENTIFIER([bool], [AC_HEADER_STDBOOL])
AN_IDENTIFIER([true], [AC_HEADER_STDBOOL])
AN_IDENTIFIER([false],[AC_HEADER_STDBOOL])
AC_DEFUN([AC_HEADER_STDBOOL],
[AC_CACHE_CHECK([for stdbool.h that conforms to C99],
   [ac_cv_header_stdbool_h],
   [AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
      [[
#include <stdbool.h>
#ifndef bool
 "error: bool is not defined"
#endif
#ifndef false
 "error: false is not defined"
#endif
#if false
 "error: false is not 0"
#endif
#ifndef true
 "error: true is not defined"
#endif
#if true != 1
 "error: true is not 1"
#endif
#ifndef __bool_true_false_are_defined
 "error: __bool_true_false_are_defined is not defined"
#endif

	struct s { _Bool s: 1; _Bool t; } s;

	char a[true == 1 ? 1 : -1];
	char b[false == 0 ? 1 : -1];
	char c[__bool_true_false_are_defined == 1 ? 1 : -1];
	char d[(bool) 0.5 == true ? 1 : -1];
	/* See body of main program for 'e'.  */
	char f[(_Bool) 0.0 == false ? 1 : -1];
	char g[true];
	char h[sizeof (_Bool)];
	char i[sizeof s.t];
	enum { j = false, k = true, l = false * true, m = true * 256 };
	/* The following fails for
	   HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
	_Bool n[m];
	char o[sizeof n == m * sizeof n[0] ? 1 : -1];
	char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
	/* Catch a bug in an HP-UX C compiler.  See
	   http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
	   http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
	 */
	_Bool q = true;
	_Bool *pq = &q;
      ]],
      [[
	bool e = &s;
	*pq |= q;
	*pq |= ! q;
	/* Refer to every declared value, to avoid compiler optimizations.  */
	return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
		+ !m + !n + !o + !p + !q + !pq);
      ]])],
      [ac_cv_header_stdbool_h=yes],
      [ac_cv_header_stdbool_h=no])])
AC_CHECK_TYPES([_Bool])
if test $ac_cv_header_stdbool_h = yes; then
  AC_DEFINE(HAVE_STDBOOL_H, 1, [Define to 1 if stdbool.h conforms to C99.])
fi
])# AC_HEADER_STDBOOL


# AC_HEADER_STDC
# --------------
AC_DEFUN([AC_HEADER_STDC],
[AC_CACHE_CHECK(for ANSI C header files, ac_cv_header_stdc,
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <float.h>
]])],
		    [ac_cv_header_stdc=yes],
		    [ac_cv_header_stdc=no])

if test $ac_cv_header_stdc = yes; then
  # SunOS 4.x string.h does not declare mem*, contrary to ANSI.
  AC_EGREP_HEADER(memchr, string.h, , ac_cv_header_stdc=no)
fi

if test $ac_cv_header_stdc = yes; then
  # ISC 2.0.2 stdlib.h does not declare free, contrary to ANSI.
  AC_EGREP_HEADER(free, stdlib.h, , ac_cv_header_stdc=no)
fi

if test $ac_cv_header_stdc = yes; then
  # /bin/cc in Irix-4.0.5 gets non-ANSI ctype macros unless using -ansi.
  AC_RUN_IFELSE([AC_LANG_SOURCE(
[[#include <ctype.h>
#include <stdlib.h>
#if ((' ' & 0x0FF) == 0x020)
# define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
# define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
#else
# define ISLOWER(c) \
		   (('a' <= (c) && (c) <= 'i') \
		     || ('j' <= (c) && (c) <= 'r') \
		     || ('s' <= (c) && (c) <= 'z'))
# define TOUPPER(c) (ISLOWER(c) ? ((c) | 0x40) : (c))
#endif

#define XOR(e, f) (((e) && !(f)) || (!(e) && (f)))
int
main ()
{
  int i;
  for (i = 0; i < 256; i++)
    if (XOR (islower (i), ISLOWER (i))
	|| toupper (i) != TOUPPER (i))
      return 2;
  return 0;
}]])], , ac_cv_header_stdc=no, :)
fi])
if test $ac_cv_header_stdc = yes; then
  AC_DEFINE(STDC_HEADERS, 1,
	    [Define to 1 if you have the ANSI C header files.])
fi
])# AC_HEADER_STDC


# AC_HEADER_SYS_WAIT
# ------------------
AC_DEFUN([AC_HEADER_SYS_WAIT],
[AC_CACHE_CHECK([for sys/wait.h that is POSIX.1 compatible],
  ac_cv_header_sys_wait_h,
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([#include <sys/types.h>
#include <sys/wait.h>
#ifndef WEXITSTATUS
# define WEXITSTATUS(stat_val) ((unsigned int) (stat_val) >> 8)
#endif
#ifndef WIFEXITED
# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
#endif
],
[  int s;
  wait (&s);
  s = WIFEXITED (s) ? WEXITSTATUS (s) : 1;])],
		 [ac_cv_header_sys_wait_h=yes],
		 [ac_cv_header_sys_wait_h=no])])
if test $ac_cv_header_sys_wait_h = yes; then
  AC_DEFINE(HAVE_SYS_WAIT_H, 1,
	    [Define to 1 if you have <sys/wait.h> that is POSIX.1 compatible.])
fi
])# AC_HEADER_SYS_WAIT


# AC_HEADER_TIME
# --------------
AC_DEFUN([AC_HEADER_TIME],
[AC_CACHE_CHECK([whether time.h and sys/time.h may both be included],
  ac_cv_header_time,
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <sys/types.h>
#include <sys/time.h>
#include <time.h>
],
[if ((struct tm *) 0)
return 0;])],
		   [ac_cv_header_time=yes],
		   [ac_cv_header_time=no])])
if test $ac_cv_header_time = yes; then
  AC_DEFINE(TIME_WITH_SYS_TIME, 1,
	    [Define to 1 if you can safely include both <sys/time.h>
	     and <time.h>.])
fi
])# AC_HEADER_TIME


# _AC_HEADER_TIOCGWINSZ_IN_TERMIOS_H
# ----------------------------------
m4_define([_AC_HEADER_TIOCGWINSZ_IN_TERMIOS_H],
[AC_CACHE_CHECK([whether termios.h defines TIOCGWINSZ],
		ac_cv_sys_tiocgwinsz_in_termios_h,
[AC_EGREP_CPP([yes],
	      [#include <sys/types.h>
#include <termios.h>
#ifdef TIOCGWINSZ
  yes
#endif
],
		ac_cv_sys_tiocgwinsz_in_termios_h=yes,
		ac_cv_sys_tiocgwinsz_in_termios_h=no)])
])# _AC_HEADER_TIOCGWINSZ_IN_TERMIOS_H


# _AC_HEADER_TIOCGWINSZ_IN_SYS_IOCTL
# ----------------------------------
m4_define([_AC_HEADER_TIOCGWINSZ_IN_SYS_IOCTL],
[AC_CACHE_CHECK([whether sys/ioctl.h defines TIOCGWINSZ],
		ac_cv_sys_tiocgwinsz_in_sys_ioctl_h,
[AC_EGREP_CPP([yes],
	      [#include <sys/types.h>
#include <sys/ioctl.h>
#ifdef TIOCGWINSZ
  yes
#endif
],
		ac_cv_sys_tiocgwinsz_in_sys_ioctl_h=yes,
		ac_cv_sys_tiocgwinsz_in_sys_ioctl_h=no)])
])# _AC_HEADER_TIOCGWINSZ_IN_SYS_IOCTL


# AC_HEADER_TIOCGWINSZ
# --------------------
# Look for a header that defines TIOCGWINSZ.
# FIXME: Is this the proper name?  Is this the proper implementation?
# I need more help.
AC_DEFUN([AC_HEADER_TIOCGWINSZ],
[_AC_HEADER_TIOCGWINSZ_IN_TERMIOS_H
if test $ac_cv_sys_tiocgwinsz_in_termios_h != yes; then
  _AC_HEADER_TIOCGWINSZ_IN_SYS_IOCTL
  if test $ac_cv_sys_tiocgwinsz_in_sys_ioctl_h = yes; then
    AC_DEFINE(GWINSZ_IN_SYS_IOCTL,1,
	      [Define to 1 if `TIOCGWINSZ' requires <sys/ioctl.h>.])
  fi
fi
])# AC_HEADER_TIOCGWINSZ


# AU::AC_UNISTD_H
# ---------------
AU_DEFUN([AC_UNISTD_H],
[AC_CHECK_HEADERS(unistd.h)])


# AU::AC_USG
# ----------
# Define `USG' if string functions are in strings.h.
AU_DEFUN([AC_USG],
[AC_MSG_CHECKING([for BSD string and memory functions])
AC_LINK_IFELSE([AC_LANG_PROGRAM([[@%:@include <strings.h>]],
				[[rindex(0, 0); bzero(0, 0);]])],
	       [AC_MSG_RESULT(yes)],
	       [AC_MSG_RESULT(no)
		AC_DEFINE(USG, 1,
			  [Define to 1 if you do not have <strings.h>, index,
			   bzero, etc... This symbol is obsolete, you should
			   not depend upon it.])])
AC_CHECK_HEADERS(string.h)],
[Remove `AC_MSG_CHECKING', `AC_LINK_IFELSE' and this warning
when you adjust your code to use HAVE_STRING_H.])


# AU::AC_MEMORY_H
# ---------------
# To be precise this macro used to be:
#
#   | AC_MSG_CHECKING(whether string.h declares mem functions)
#   | AC_EGREP_HEADER(memchr, string.h, ac_found=yes, ac_found=no)
#   | AC_MSG_RESULT($ac_found)
#   | if test $ac_found = no; then
#   |	AC_CHECK_HEADER(memory.h, [AC_DEFINE(NEED_MEMORY_H)])
#   | fi
#
# But it is better to check for both headers, and alias NEED_MEMORY_H to
# HAVE_MEMORY_H.
AU_DEFUN([AC_MEMORY_H],
[AC_CHECK_HEADER(memory.h,
		[AC_DEFINE([NEED_MEMORY_H], 1,
			   [Same as `HAVE_MEMORY_H', don't depend on me.])])
AC_CHECK_HEADERS(string.h memory.h)],
[Remove this warning and
`AC_CHECK_HEADER(memory.h, AC_DEFINE(...))' when you adjust your code to
use HAVE_STRING_H and HAVE_MEMORY_H, not NEED_MEMORY_H.])


# AU::AC_DIR_HEADER
# -----------------
# Like calling `AC_HEADER_DIRENT' and `AC_FUNC_CLOSEDIR_VOID', but
# defines a different set of C preprocessor macros to indicate which
# header file is found.
AU_DEFUN([AC_DIR_HEADER],
[AC_HEADER_DIRENT
AC_FUNC_CLOSEDIR_VOID
test ac_cv_header_dirent_dirent_h &&
  AC_DEFINE([DIRENT], 1, [Same as `HAVE_DIRENT_H', don't depend on me.])
test ac_cv_header_dirent_sys_ndir_h &&
  AC_DEFINE([SYSNDIR], 1, [Same as `HAVE_SYS_NDIR_H', don't depend on me.])
test ac_cv_header_dirent_sys_dir_h &&
  AC_DEFINE([SYSDIR], 1, [Same as `HAVE_SYS_DIR_H', don't depend on me.])
test ac_cv_header_dirent_ndir_h &&
  AC_DEFINE([NDIR], 1, [Same as `HAVE_NDIR_H', don't depend on me.])],
[Remove this warning and the four `AC_DEFINE' when you
adjust your code to use `AC_HEADER_DIRENT'.])