# This file is part of Autoconf.			-*- Autoconf -*-
# Programming languages support.
# Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 Free Software
# Foundation, Inc.
#
# 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 2, 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.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
#
# As a special exception, the Free Software Foundation gives unlimited
# permission to copy, distribute and modify the configure scripts that
# are the output of Autoconf.  You need not follow the terms of the GNU
# General Public License when using or distributing such scripts, even
# though portions of the text of Autoconf appear in them.  The GNU
# General Public License (GPL) does govern all other use of the material
# that constitutes the Autoconf program.
#
# Certain portions of the Autoconf source text are designed to be copied
# (in certain cases, depending on the input) into the output of
# Autoconf.  We call these the "data" portions.  The rest of the Autoconf
# source text consists of comments plus executable code that decides which
# of the data portions to output in any given case.  We call these
# comments and executable code the "non-data" portions.  Autoconf never
# copies any of the non-data portions into its output.
#
# This special exception to the GPL applies to versions of Autoconf
# released by the Free Software Foundation.  When you make and
# distribute a modified version of Autoconf, you may extend this special
# exception to the GPL to apply to your modified version as well, *unless*
# your modified version has the potential to copy into its output some
# of the text that was the non-data portion of the version that you started
# with.  (In other words, unless your change moves or copies text from
# the non-data portions to the data portions.)  If your modification has
# such potential, you must delete any notice of this special exception
# to the GPL from your modified version.
#
# Written by David MacKenzie, with help from
# Akim Demaille, Paul Eggert,
# Franc,ois Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
# Roland McGrath, Noah Friedman, david d zuhn, and many others.


# -------------------- #
# 1b. The C language.  #
# -------------------- #


# AC_LANG(C)
# ----------
# CFLAGS is not in ac_cpp because -g, -O, etc. are not valid cpp options.
m4_define([AC_LANG(C)],
[ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&AS_MESSAGE_LOG_FD'
ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&AS_MESSAGE_LOG_FD'
ac_compiler_gnu=$ac_cv_c_compiler_gnu
])


# AC_LANG_C
# ---------
AU_DEFUN([AC_LANG_C], [AC_LANG(C)])


# _AC_LANG_ABBREV(C)
# ------------------
m4_define([_AC_LANG_ABBREV(C)], [c])


# _AC_LANG_PREFIX(C)
# ------------------
m4_define([_AC_LANG_PREFIX(C)], [C])


# ---------------------- #
# 1c. The C++ language.  #
# ---------------------- #


# AC_LANG(C++)
# ------------
# CXXFLAGS is not in ac_cpp because -g, -O, etc. are not valid cpp options.
m4_define([AC_LANG(C++)],
[ac_ext=cpp
ac_cpp='$CXXCPP $CPPFLAGS'
ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&AS_MESSAGE_LOG_FD'
ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&AS_MESSAGE_LOG_FD'
ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
])


# AC_LANG_CPLUSPLUS
# -----------------
AU_DEFUN([AC_LANG_CPLUSPLUS], [AC_LANG(C++)])


# _AC_LANG_ABBREV(C++)
# --------------------
m4_define([_AC_LANG_ABBREV(C++)], [cxx])


# _AC_LANG_PREFIX(C++)
# --------------------
m4_define([_AC_LANG_PREFIX(C++)], [CXX])



# ------------------------------ #
# 1d. The Objective C language.  #
# ------------------------------ #


# AC_LANG(Objective C)
# --------------------
m4_define([AC_LANG(Objective C)],
[ac_ext=m
ac_cpp='$OBJCPP $CPPFLAGS'
ac_compile='$OBJC -c $OBJCFLAGS $CPPFLAGS conftest.$ac_ext >&AS_MESSAGE_LOG_FD'
ac_link='$OBJC -o conftest$ac_exeext $OBJCFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&AS_MESSAGE_LOG_FD'
ac_compiler_gnu=$ac_cv_objc_compiler_gnu
])


# AC_LANG_OBJC
# ------------
AU_DEFUN([AC_LANG_OBJC], [AC_LANG(Objective C)])


# _AC_LANG_ABBREV(Objective C)
# ----------------------------
m4_define([_AC_LANG_ABBREV(Objective C)], [objc])


# _AC_LANG_PREFIX(Objective C)
# ----------------------------
m4_define([_AC_LANG_PREFIX(Objective C)], [OBJC])



## ---------------------- ##
## 2.Producing programs.  ##
## ---------------------- ##


# --------------- #
# 2b. C sources.  #
# --------------- #

# AC_LANG_SOURCE(C)(BODY)
# -----------------------
# We can't use '#line $LINENO "configure"' here, since
# Sun c89 (Sun WorkShop 6 update 2 C 5.3 Patch 111679-08 2002/05/09)
# rejects $LINENO greater than 32767, and some configure scripts
# are longer than 32767 lines.
m4_define([AC_LANG_SOURCE(C)],
[/* confdefs.h.  */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h.  */
$1])


# AC_LANG_PROGRAM(C)([PROLOGUE], [BODY])
# --------------------------------------
m4_define([AC_LANG_PROGRAM(C)],
[$1
m4_ifdef([_AC_LANG_PROGRAM_C_F77_HOOKS], [_AC_LANG_PROGRAM_C_F77_HOOKS])[]dnl
m4_ifdef([_AC_LANG_PROGRAM_C_FC_HOOKS], [_AC_LANG_PROGRAM_C_FC_HOOKS])[]dnl
int
main ()
{
dnl Do *not* indent the following line: there may be CPP directives.
dnl Don't move the `;' right after for the same reason.
$2
  ;
  return 0;
}])


# AC_LANG_CALL(C)(PROLOGUE, FUNCTION)
# -----------------------------------
# Avoid conflicting decl of main.
m4_define([AC_LANG_CALL(C)],
[AC_LANG_PROGRAM([$1
m4_if([$2], [main], ,
[/* Override any GCC internal prototype to avoid an error.
   Use char because int might match the return type of a GCC
   builtin and then its argument prototype would still apply.  */
#ifdef __cplusplus
extern "C"
#endif
char $2 ();])], [return $2 ();])])


# AC_LANG_FUNC_LINK_TRY(C)(FUNCTION)
# ----------------------------------
# Don't include <ctype.h> because on OSF/1 3.0 it includes
# <sys/types.h> which includes <sys/select.h> which contains a
# prototype for select.  Similarly for bzero.
#
# This test used to merely assign f=$1 in main(), but that was
# optimized away by HP unbundled cc A.05.36 for ia64 under +O3,
# presumably on the basis that there's no need to do that store if the
# program is about to exit.  Conversely, the AIX linker optimizes an
# unused external declaration that initializes f=$1.  So this test
# program has both an external initialization of f, and a use of f in
# main that affects the exit status.
#
m4_define([AC_LANG_FUNC_LINK_TRY(C)],
[AC_LANG_PROGRAM(
[/* Define $1 to an innocuous variant, in case <limits.h> declares $1.
   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
#define $1 innocuous_$1

/* System header to define __stub macros and hopefully few prototypes,
    which can conflict with char $1 (); below.
    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
    <limits.h> exists even on freestanding compilers.  */

#ifdef __STDC__
# include <limits.h>
#else
# include <assert.h>
#endif

#undef $1

/* Override any GCC internal prototype to avoid an error.
   Use char because int might match the return type of a GCC
   builtin and then its argument prototype would still apply.  */
#ifdef __cplusplus
extern "C"
#endif
char $1 ();
/* The GNU C library defines this for functions which it implements
    to always fail with ENOSYS.  Some functions are actually named
    something starting with __ and the normal name is an alias.  */
#if defined __stub_$1 || defined __stub___$1
choke me
#endif
], [return $1 ();])])


# AC_LANG_BOOL_COMPILE_TRY(C)(PROLOGUE, EXPRESSION)
# -------------------------------------------------
# Return a program that is valid if EXPRESSION is nonzero.
# EXPRESSION must be an integer constant expression.
# Be sure to use this array to avoid `unused' warnings, which are even
# errors with `-W error'.
m4_define([AC_LANG_BOOL_COMPILE_TRY(C)],
[AC_LANG_PROGRAM([$1], [static int test_array @<:@1 - 2 * !($2)@:>@;
test_array @<:@0@:>@ = 0
])])


# AC_LANG_INT_SAVE(C)(PROLOGUE, EXPRESSION)
# -----------------------------------------
# We need `stdio.h' to open a `FILE' and `stdlib.h' for `exit'.
# But we include them only after the EXPRESSION has been evaluated.
m4_define([AC_LANG_INT_SAVE(C)],
[AC_LANG_PROGRAM([$1
static long int longval () { return $2; }
static unsigned long int ulongval () { return $2; }
@%:@include <stdio.h>
@%:@include <stdlib.h>],
[
  FILE *f = fopen ("conftest.val", "w");
  if (! f)
    return 1;
  if (($2) < 0)
    {
      long int i = longval ();
      if (i != ($2))
	return 1;
      fprintf (f, "%ld\n", i);
    }
  else
    {
      unsigned long int i = ulongval ();
      if (i != ($2))
	return 1;
      fprintf (f, "%lu\n", i);
    }
  return ferror (f) || fclose (f) != 0;
])])


# ----------------- #
# 2c. C++ sources.  #
# ----------------- #

# AC_LANG_SOURCE(C++)(BODY)
# -------------------------
m4_copy([AC_LANG_SOURCE(C)], [AC_LANG_SOURCE(C++)])


# AC_LANG_PROGRAM(C++)([PROLOGUE], [BODY])
# ----------------------------------------
m4_copy([AC_LANG_PROGRAM(C)], [AC_LANG_PROGRAM(C++)])


# AC_LANG_CALL(C++)(PROLOGUE, FUNCTION)
# -------------------------------------
m4_copy([AC_LANG_CALL(C)], [AC_LANG_CALL(C++)])


# AC_LANG_FUNC_LINK_TRY(C++)(FUNCTION)
# ------------------------------------
m4_copy([AC_LANG_FUNC_LINK_TRY(C)], [AC_LANG_FUNC_LINK_TRY(C++)])


# AC_LANG_BOOL_COMPILE_TRY(C++)(PROLOGUE, EXPRESSION)
# ---------------------------------------------------
m4_copy([AC_LANG_BOOL_COMPILE_TRY(C)], [AC_LANG_BOOL_COMPILE_TRY(C++)])


# AC_LANG_INT_SAVE(C++)(PROLOGUE, EXPRESSION)
# -------------------------------------------
m4_copy([AC_LANG_INT_SAVE(C)], [AC_LANG_INT_SAVE(C++)])



# ------------------------- #
# 2d. Objective C sources.  #
# ------------------------- #

# AC_LANG_SOURCE(Objective C)(BODY)
# ---------------------------------
m4_copy([AC_LANG_SOURCE(C)], [AC_LANG_SOURCE(Objective C)])


# AC_LANG_PROGRAM(Objective C)([PROLOGUE], [BODY])
# ------------------------------------------------
m4_copy([AC_LANG_PROGRAM(C)], [AC_LANG_PROGRAM(Objective C)])


# AC_LANG_CALL(Objective C)(PROLOGUE, FUNCTION)
# ---------------------------------------------
m4_copy([AC_LANG_CALL(C)], [AC_LANG_CALL(Objective C)])


# AC_LANG_FUNC_LINK_TRY(Objective C)(FUNCTION)
# --------------------------------------------
m4_copy([AC_LANG_FUNC_LINK_TRY(C)], [AC_LANG_FUNC_LINK_TRY(Objective C)])


# AC_LANG_BOOL_COMPILE_TRY(Objective C)(PROLOGUE, EXPRESSION)
# -----------------------------------------------------------
m4_copy([AC_LANG_BOOL_COMPILE_TRY(C)], [AC_LANG_BOOL_COMPILE_TRY(Objective C)])


# AC_LANG_INT_SAVE(Objective C)(PROLOGUE, EXPRESSION)
# ---------------------------------------------------
m4_copy([AC_LANG_INT_SAVE(C)], [AC_LANG_INT_SAVE(Objective C)])



## -------------------------------------------- ##
## 3. Looking for Compilers and Preprocessors.  ##
## -------------------------------------------- ##

# -------------------- #
# 3b. The C compiler.  #
# -------------------- #


# _AC_ARG_VAR_CPPFLAGS
# --------------------
# Document and register CPPFLAGS, which is used by
# AC_PROG_{CC, CPP, CXX, CXXCPP, OBJC, OBJCPP}.
AC_DEFUN([_AC_ARG_VAR_CPPFLAGS],
[AC_ARG_VAR([CPPFLAGS],
	    [C/C++/Objective C preprocessor flags, e.g. -I<include dir>
	     if you have headers in a nonstandard directory <include dir>])])


# _AC_ARG_VAR_LDFLAGS
# -------------------
# Document and register LDFLAGS, which is used by
# AC_PROG_{CC, CXX, F77}.
AC_DEFUN([_AC_ARG_VAR_LDFLAGS],
[AC_ARG_VAR([LDFLAGS],
	    [linker flags, e.g. -L<lib dir> if you have libraries in a
	     nonstandard directory <lib dir>])])



# AC_LANG_PREPROC(C)
# -------------------
# Find the C preprocessor.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_PREPROC(C)],
[AC_REQUIRE([AC_PROG_CPP])])


# _AC_PROG_PREPROC_WORKS_IFELSE(IF-WORKS, IF-NOT)
# -----------------------------------------------
# Check if $ac_cpp is a working preprocessor that can flag absent
# includes either by the exit status or by warnings.
# Set ac_cpp_err to a non-empty value if the preprocessor failed.
# This macro is for all languages, not only C.
AC_DEFUN([_AC_PROG_PREPROC_WORKS_IFELSE],
[ac_preproc_ok=false
for ac_[]_AC_LANG_ABBREV[]_preproc_warn_flag in '' yes
do
  # Use a header file that comes with gcc, so configuring glibc
  # with a fresh cross-compiler works.
  # Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
  # <limits.h> exists even on freestanding compilers.
  # On the NeXT, cc -E runs the code through the compiler's parser,
  # not just through cpp. "Syntax error" is here to catch this case.
  _AC_PREPROC_IFELSE([AC_LANG_SOURCE([[@%:@ifdef __STDC__
@%:@ include <limits.h>
@%:@else
@%:@ include <assert.h>
@%:@endif
		     Syntax error]])],
		     [],
		     [# Broken: fails on valid input.
continue])

  # OK, works on sane cases.  Now check whether nonexistent headers
  # can be detected and how.
  _AC_PREPROC_IFELSE([AC_LANG_SOURCE([[@%:@include <ac_nonexistent.h>]])],
		     [# Broken: success on invalid input.
continue],
		     [# Passes both tests.
ac_preproc_ok=:
break])

done
# Because of `break', _AC_PREPROC_IFELSE's cleaning code was skipped.
rm -f conftest.err conftest.$ac_ext
AS_IF([$ac_preproc_ok], [$1], [$2])])# _AC_PROG_PREPROC_WORKS_IFELSE


# AC_PROG_CPP
# -----------
# Find a working C preprocessor.
# We shouldn't have to require AC_PROG_CC, but this is due to the concurrency
# between the AC_LANG_COMPILER_REQUIRE family and that of AC_PROG_CC.
AN_MAKEVAR([CPP], [AC_PROG_CPP])
AN_PROGRAM([cpp], [AC_PROG_CPP])
AC_DEFUN([AC_PROG_CPP],
[AC_REQUIRE([AC_PROG_CC])dnl
AC_ARG_VAR([CPP],      [C preprocessor])dnl
_AC_ARG_VAR_CPPFLAGS()dnl
AC_LANG_PUSH(C)dnl
AC_MSG_CHECKING([how to run the C preprocessor])
# On Suns, sometimes $CPP names a directory.
if test -n "$CPP" && test -d "$CPP"; then
  CPP=
fi
if test -z "$CPP"; then
  AC_CACHE_VAL([ac_cv_prog_CPP],
  [dnl
    # Double quotes because CPP needs to be expanded
    for CPP in "$CC -E" "$CC -E -traditional-cpp" "/lib/cpp"
    do
      _AC_PROG_PREPROC_WORKS_IFELSE([break])
    done
    ac_cv_prog_CPP=$CPP
  ])dnl
  CPP=$ac_cv_prog_CPP
else
  ac_cv_prog_CPP=$CPP
fi
AC_MSG_RESULT([$CPP])
_AC_PROG_PREPROC_WORKS_IFELSE([],
		[AC_MSG_FAILURE([C preprocessor "$CPP" fails sanity check])])
AC_SUBST(CPP)dnl
AC_LANG_POP(C)dnl
])# AC_PROG_CPP

# AC_PROG_CPP_WERROR
# ------------------
# Treat warnings from the preprocessor as errors.
AC_DEFUN([AC_PROG_CPP_WERROR],
[AC_REQUIRE([AC_PROG_CPP])dnl
ac_c_preproc_warn_flag=yes])# AC_PROG_CPP_WERROR

# AC_LANG_COMPILER(C)
# -------------------
# Find the C compiler.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_COMPILER(C)],
[AC_REQUIRE([AC_PROG_CC])])


# ac_cv_prog_gcc
# --------------
# We used to name the cache variable this way.
AU_DEFUN([ac_cv_prog_gcc],
[ac_cv_c_compiler_gnu])


# AC_PROG_CC([COMPILER ...])
# --------------------------
# COMPILER ... is a space separated list of C compilers to search for.
# This just gives the user an opportunity to specify an alternative
# search list for the C compiler.
AN_MAKEVAR([CC],  [AC_PROG_CC])
AN_PROGRAM([cc],  [AC_PROG_CC])
AN_PROGRAM([gcc], [AC_PROG_CC])
AC_DEFUN([AC_PROG_CC],
[AC_LANG_PUSH(C)dnl
AC_ARG_VAR([CC],     [C compiler command])dnl
AC_ARG_VAR([CFLAGS], [C compiler flags])dnl
_AC_ARG_VAR_LDFLAGS()dnl
_AC_ARG_VAR_CPPFLAGS()dnl
m4_ifval([$1],
      [AC_CHECK_TOOLS(CC, [$1])],
[AC_CHECK_TOOL(CC, gcc)
if test -z "$CC"; then
  dnl Here we want:
  dnl	AC_CHECK_TOOL(CC, cc)
  dnl but without the check for a tool without the prefix.
  dnl Until the check is removed from there, copy the code:
  if test -n "$ac_tool_prefix"; then
    AC_CHECK_PROG(CC, [${ac_tool_prefix}cc], [${ac_tool_prefix}cc])
  fi
fi
if test -z "$CC"; then
  AC_CHECK_PROG(CC, cc, cc, , , /usr/ucb/cc)
fi
if test -z "$CC"; then
  AC_CHECK_TOOLS(CC, cl.exe)
fi
])

test -z "$CC" && AC_MSG_FAILURE([no acceptable C compiler found in \$PATH])

# Provide some information about the compiler.
_AS_ECHO_LOG([checking for _AC_LANG compiler version])
ac_compiler=`set X $ac_compile; echo $[2]`
_AC_DO([$ac_compiler --version >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -v >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -V >&AS_MESSAGE_LOG_FD])

m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
_AC_LANG_COMPILER_GNU
GCC=`test $ac_compiler_gnu = yes && echo yes`
_AC_PROG_CC_G
_AC_PROG_CC_C89
AC_LANG_POP(C)dnl
])# AC_PROG_CC


# _AC_PROG_CC_G
# -------------
# Check whether -g works, even if CFLAGS is set, in case the package
# plays around with CFLAGS (such as to build both debugging and normal
# versions of a library), tasteless as that idea is.
# Don't consider -g to work if it generates warnings when plain compiles don't.
m4_define([_AC_PROG_CC_G],
[ac_test_CFLAGS=${CFLAGS+set}
ac_save_CFLAGS=$CFLAGS
AC_CACHE_CHECK(whether $CC accepts -g, ac_cv_prog_cc_g,
  [ac_save_c_werror_flag=$ac_c_werror_flag
   ac_c_werror_flag=yes
   ac_cv_prog_cc_g=no
   CFLAGS="-g"
   _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
     [ac_cv_prog_cc_g=yes],
     [CFLAGS=""
      _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	[],
	[ac_c_werror_flag=$ac_save_c_werror_flag
	 CFLAGS="-g"
	 _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	   [ac_cv_prog_cc_g=yes])])])
   ac_c_werror_flag=$ac_save_c_werror_flag])
if test "$ac_test_CFLAGS" = set; then
  CFLAGS=$ac_save_CFLAGS
elif test $ac_cv_prog_cc_g = yes; then
  if test "$GCC" = yes; then
    CFLAGS="-g -O2"
  else
    CFLAGS="-g"
  fi
else
  if test "$GCC" = yes; then
    CFLAGS="-O2"
  else
    CFLAGS=
  fi
fi[]dnl
])# _AC_PROG_CC_G


# AC_PROG_GCC_TRADITIONAL
# -----------------------
AN_FUNCTION([ioctl],   [AC_PROG_GCC_TRADITIONAL])
AC_DEFUN([AC_PROG_GCC_TRADITIONAL],
[if test $ac_cv_c_compiler_gnu = yes; then
    AC_CACHE_CHECK(whether $CC needs -traditional,
      ac_cv_prog_gcc_traditional,
[  ac_pattern="Autoconf.*'x'"
  AC_EGREP_CPP($ac_pattern, [#include <sgtty.h>
Autoconf TIOCGETP],
  ac_cv_prog_gcc_traditional=yes, ac_cv_prog_gcc_traditional=no)

  if test $ac_cv_prog_gcc_traditional = no; then
    AC_EGREP_CPP($ac_pattern, [#include <termio.h>
Autoconf TCGETA],
    ac_cv_prog_gcc_traditional=yes)
  fi])
  if test $ac_cv_prog_gcc_traditional = yes; then
    CC="$CC -traditional"
  fi
fi
])# AC_PROG_GCC_TRADITIONAL


# AC_PROG_CC_C_O
# --------------
AC_DEFUN([AC_PROG_CC_C_O],
[AC_REQUIRE([AC_PROG_CC])dnl
if test "x$CC" != xcc; then
  AC_MSG_CHECKING([whether $CC and cc understand -c and -o together])
else
  AC_MSG_CHECKING([whether cc understands -c and -o together])
fi
set dummy $CC; ac_cc=`echo $[2] |
		      sed 's/[[^a-zA-Z0-9_]]/_/g;s/^[[0-9]]/_/'`
AC_CACHE_VAL(ac_cv_prog_cc_${ac_cc}_c_o,
[AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
# Make sure it works both with $CC and with simple cc.
# We do the test twice because some compilers refuse to overwrite an
# existing .o file with -o, though they will create one.
ac_try='$CC -c conftest.$ac_ext -o conftest2.$ac_objext >&AS_MESSAGE_LOG_FD'
rm -f conftest2.*
if _AC_DO_VAR(ac_try) &&
   test -f conftest2.$ac_objext && _AC_DO_VAR(ac_try);
then
  eval ac_cv_prog_cc_${ac_cc}_c_o=yes
  if test "x$CC" != xcc; then
    # Test first that cc exists at all.
    if _AC_DO_TOKENS(cc -c conftest.$ac_ext >&AS_MESSAGE_LOG_FD); then
      ac_try='cc -c conftest.$ac_ext -o conftest2.$ac_objext >&AS_MESSAGE_LOG_FD'
      rm -f conftest2.*
      if _AC_DO_VAR(ac_try) &&
	 test -f conftest2.$ac_objext && _AC_DO_VAR(ac_try);
      then
	# cc works too.
	:
      else
	# cc exists but doesn't like -o.
	eval ac_cv_prog_cc_${ac_cc}_c_o=no
      fi
    fi
  fi
else
  eval ac_cv_prog_cc_${ac_cc}_c_o=no
fi
rm -f core conftest*
])dnl
if eval test \$ac_cv_prog_cc_${ac_cc}_c_o = yes; then
  AC_MSG_RESULT([yes])
else
  AC_MSG_RESULT([no])
  AC_DEFINE(NO_MINUS_C_MINUS_O, 1,
	   [Define to 1 if your C compiler doesn't accept -c and -o together.])
fi
])# AC_PROG_CC_C_O


# ---------------------- #
# 3c. The C++ compiler.  #
# ---------------------- #


# AC_LANG_PREPROC(C++)
# ---------------------
# Find the C++ preprocessor.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_PREPROC(C++)],
[AC_REQUIRE([AC_PROG_CXXCPP])])


# AC_PROG_CXXCPP
# --------------
# Find a working C++ preprocessor.
# We shouldn't have to require AC_PROG_CC, but this is due to the concurrency
# between the AC_LANG_COMPILER_REQUIRE family and that of AC_PROG_CXX.
AC_DEFUN([AC_PROG_CXXCPP],
[AC_REQUIRE([AC_PROG_CXX])dnl
AC_ARG_VAR([CXXCPP],   [C++ preprocessor])dnl
_AC_ARG_VAR_CPPFLAGS()dnl
AC_LANG_PUSH(C++)dnl
AC_MSG_CHECKING([how to run the C++ preprocessor])
if test -z "$CXXCPP"; then
  AC_CACHE_VAL(ac_cv_prog_CXXCPP,
  [dnl
    # Double quotes because CXXCPP needs to be expanded
    for CXXCPP in "$CXX -E" "/lib/cpp"
    do
      _AC_PROG_PREPROC_WORKS_IFELSE([break])
    done
    ac_cv_prog_CXXCPP=$CXXCPP
  ])dnl
  CXXCPP=$ac_cv_prog_CXXCPP
else
  ac_cv_prog_CXXCPP=$CXXCPP
fi
AC_MSG_RESULT([$CXXCPP])
_AC_PROG_PREPROC_WORKS_IFELSE([],
	  [AC_MSG_FAILURE([C++ preprocessor "$CXXCPP" fails sanity check])])
AC_SUBST(CXXCPP)dnl
AC_LANG_POP(C++)dnl
])# AC_PROG_CXXCPP


# AC_LANG_COMPILER(C++)
# ---------------------
# Find the C++ compiler.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_COMPILER(C++)],
[AC_REQUIRE([AC_PROG_CXX])])


# ac_cv_prog_gxx
# --------------
# We used to name the cache variable this way.
AU_DEFUN([ac_cv_prog_gxx],
[ac_cv_cxx_compiler_gnu])


# AC_PROG_CXX([LIST-OF-COMPILERS])
# --------------------------------
# LIST-OF-COMPILERS is a space separated list of C++ compilers to search
# for (if not specified, a default list is used).  This just gives the
# user an opportunity to specify an alternative search list for the C++
# compiler.
# aCC	HP-UX C++ compiler much better than `CC', so test before.
# FCC   Fujitsu C++ compiler
# KCC	KAI C++ compiler
# RCC	Rational C++
# xlC_r	AIX C Set++ (with support for reentrant code)
# xlC	AIX C Set++
AN_MAKEVAR([CXX],  [AC_PROG_CXX])
AN_PROGRAM([CC],   [AC_PROG_CXX])
AN_PROGRAM([c++],  [AC_PROG_CXX])
AN_PROGRAM([g++],  [AC_PROG_CXX])
AC_DEFUN([AC_PROG_CXX],
[AC_LANG_PUSH(C++)dnl
AC_ARG_VAR([CXX],      [C++ compiler command])dnl
AC_ARG_VAR([CXXFLAGS], [C++ compiler flags])dnl
_AC_ARG_VAR_LDFLAGS()dnl
_AC_ARG_VAR_CPPFLAGS()dnl
_AC_ARG_VAR_PRECIOUS([CCC])dnl
if test -z "$CXX"; then
  if test -n "$CCC"; then
    CXX=$CCC
  else
    AC_CHECK_TOOLS(CXX,
		   [m4_default([$1],
			       [g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC])],
		   g++)
  fi
fi
# Provide some information about the compiler.
_AS_ECHO_LOG([checking for _AC_LANG compiler version])
ac_compiler=`set X $ac_compile; echo $[2]`
_AC_DO([$ac_compiler --version >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -v >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -V >&AS_MESSAGE_LOG_FD])

m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
_AC_LANG_COMPILER_GNU
GXX=`test $ac_compiler_gnu = yes && echo yes`
_AC_PROG_CXX_G
AC_LANG_POP(C++)dnl
])# AC_PROG_CXX


# _AC_PROG_CXX_G
# --------------
# Check whether -g works, even if CXXFLAGS is set, in case the package
# plays around with CXXFLAGS (such as to build both debugging and
# normal versions of a library), tasteless as that idea is.
# Don't consider -g to work if it generates warnings when plain compiles don't.
m4_define([_AC_PROG_CXX_G],
[ac_test_CXXFLAGS=${CXXFLAGS+set}
ac_save_CXXFLAGS=$CXXFLAGS
AC_CACHE_CHECK(whether $CXX accepts -g, ac_cv_prog_cxx_g,
  [ac_save_cxx_werror_flag=$ac_cxx_werror_flag
   ac_cxx_werror_flag=yes
   ac_cv_prog_cxx_g=no
   CXXFLAGS="-g"
   _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
     [ac_cv_prog_cxx_g=yes],
     [CXXFLAGS=""
      _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	[],
	[ac_cxx_werror_flag=$ac_save_cxx_werror_flag
	 CXXFLAGS="-g"
	 _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	   [ac_cv_prog_cxx_g=yes])])])
   ac_cxx_werror_flag=$ac_save_cxx_werror_flag])
if test "$ac_test_CXXFLAGS" = set; then
  CXXFLAGS=$ac_save_CXXFLAGS
elif test $ac_cv_prog_cxx_g = yes; then
  if test "$GXX" = yes; then
    CXXFLAGS="-g -O2"
  else
    CXXFLAGS="-g"
  fi
else
  if test "$GXX" = yes; then
    CXXFLAGS="-O2"
  else
    CXXFLAGS=
  fi
fi[]dnl
])# _AC_PROG_CXX_G


# AC_PROG_CXX_C_O
# ---------------
# Test if the C++ compiler accepts the options `-c' and `-o'
# simultaneously, and define `CXX_NO_MINUS_C_MINUS_O' if it does not.
AC_DEFUN([AC_PROG_CXX_C_O],
[AC_REQUIRE([AC_PROG_CXX])dnl
AC_LANG_PUSH([C++])dnl
AC_CACHE_CHECK([whether $CXX understands -c and -o together],
               [ac_cv_prog_cxx_c_o],
[AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
# We test twice because some compilers refuse to overwrite an existing
# `.o' file with `-o', although they will create one.
ac_try='$CXX $CXXFLAGS -c conftest.$ac_ext -o conftest2.$ac_objext >&AS_MESSAGE_LOG_FD'
rm -f conftest2.*
if _AC_DO_VAR(ac_try) &&
     test -f conftest2.$ac_objext &&
     _AC_DO_VAR(ac_try); then
  ac_cv_prog_cxx_c_o=yes
else
  ac_cv_prog_cxx_c_o=no
fi
rm -f conftest*])
if test $ac_cv_prog_cxx_c_o = no; then
  AC_DEFINE(CXX_NO_MINUS_C_MINUS_O, 1,
            [Define to 1 if your C++ compiler doesn't accept
             -c and -o together.])
fi
AC_LANG_POP([C++])dnl
])# AC_PROG_CXX_C_O


# ------------------------------ #
# 3d. The Objective C compiler.  #
# ------------------------------ #


# AC_LANG_PREPROC(Objective C)
# ----------------------------
# Find the Objective C preprocessor.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_PREPROC(Objective C)],
[AC_REQUIRE([AC_PROG_OBJCPP])])


# AC_PROG_OBJCPP
# --------------
# Find a working Objective C preprocessor.
AC_DEFUN([AC_PROG_OBJCPP],
[AC_REQUIRE([AC_PROG_OBJC])dnl
AC_ARG_VAR([OBJCPP],   [Objective C preprocessor])dnl
_AC_ARG_VAR_CPPFLAGS()dnl
AC_LANG_PUSH(Objective C)dnl
AC_MSG_CHECKING([how to run the Objective C preprocessor])
if test -z "$OBJCPP"; then
  AC_CACHE_VAL(ac_cv_prog_OBJCPP,
  [dnl
    # Double quotes because OBJCPP needs to be expanded
    for OBJCPP in "$OBJC -E" "/lib/cpp"
    do
      _AC_PROG_PREPROC_WORKS_IFELSE([break])
    done
    ac_cv_prog_OBJCPP=$OBJCPP
  ])dnl
  OBJCPP=$ac_cv_prog_OBJCPP
else
  ac_cv_prog_OBJCPP=$OBJCPP
fi
AC_MSG_RESULT([$OBJCPP])
_AC_PROG_PREPROC_WORKS_IFELSE([],
	  [AC_MSG_FAILURE([Objective C preprocessor "$OBJCPP" fails sanity check])])
AC_SUBST(OBJCPP)dnl
AC_LANG_POP(Objective C)dnl
])# AC_PROG_OBJCPP


# AC_LANG_COMPILER(Objective C)
# -----------------------------
# Find the Objective C compiler.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_COMPILER(Objective C)],
[AC_REQUIRE([AC_PROG_OBJC])])



# AC_PROG_OBJC([LIST-OF-COMPILERS])
# ---------------------------------
# LIST-OF-COMPILERS is a space separated list of Objective C compilers to
# search for (if not specified, a default list is used).  This just gives
# the user an opportunity to specify an alternative search list for the
# Objective C compiler.
# objcc StepStone Objective-C compiler (also "standard" name for OBJC)
# objc  David Stes' POC.  If you installed this, you likely want it.
# cc    Native C compiler (for instance, Apple).
# CC    You never know.
AN_MAKEVAR([OBJC],  [AC_PROG_OBJC])
AN_PROGRAM([objcc],  [AC_PROG_OBJC])
AN_PROGRAM([objc],  [AC_PROG_OBJC])
AC_DEFUN([AC_PROG_OBJC],
[AC_LANG_PUSH(Objective C)dnl
AC_ARG_VAR([OBJC],      [Objective C compiler command])dnl
AC_ARG_VAR([OBJCFLAGS], [Objective C compiler flags])dnl
_AC_ARG_VAR_LDFLAGS()dnl
_AC_ARG_VAR_CPPFLAGS()dnl
_AC_ARG_VAR_PRECIOUS([OBJC])dnl
AC_CHECK_TOOLS(OBJC,
	       [m4_default([$1], [gcc objcc objc cc CC])],
	       gcc)
# Provide some information about the compiler.
_AS_ECHO_LOG([checking for _AC_LANG compiler version])
ac_compiler=`set X $ac_compile; echo $[2]`
_AC_DO([$ac_compiler --version >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -v >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -V >&AS_MESSAGE_LOG_FD])

m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
_AC_LANG_COMPILER_GNU
GOBJC=`test $ac_compiler_gnu = yes && echo yes`
_AC_PROG_OBJC_G
AC_LANG_POP(Objective C)dnl
])# AC_PROG_OBJC


# _AC_PROG_OBJC_G
# ---------------
# Check whether -g works, even if OBJCFLAGS is set, in case the package
# plays around with OBJCFLAGS (such as to build both debugging and
# normal versions of a library), tasteless as that idea is.
# Don't consider -g to work if it generates warnings when plain compiles don't.
m4_define([_AC_PROG_OBJC_G],
[ac_test_OBJCFLAGS=${OBJCFLAGS+set}
ac_save_OBJCFLAGS=$OBJCFLAGS
AC_CACHE_CHECK(whether $OBJC accepts -g, ac_cv_prog_objc_g,
  [ac_save_objc_werror_flag=$ac_objc_werror_flag
   ac_objc_werror_flag=yes
   ac_cv_prog_objc_g=no
   OBJCFLAGS="-g"
   _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
     [ac_cv_prog_objc_g=yes],
     [OBJCFLAGS=""
      _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	[],
	[ac_objc_werror_flag=$ac_save_objc_werror_flag
	 OBJCFLAGS="-g"
	 _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	   [ac_cv_prog_objc_g=yes])])])
   ac_objc_werror_flag=$ac_save_objc_werror_flag])
if test "$ac_test_OBJCFLAGS" = set; then
  OBJCFLAGS=$ac_save_OBJCFLAGS
elif test $ac_cv_prog_objc_g = yes; then
  if test "$GOBJC" = yes; then
    OBJCFLAGS="-g -O2"
  else
    OBJCFLAGS="-g"
  fi
else
  if test "$GOBJC" = yes; then
    OBJCFLAGS="-O2"
  else
    OBJCFLAGS=
  fi
fi[]dnl
])# _AC_PROG_OBJC_G






## ------------------------------- ##
## 4. Compilers' characteristics.  ##
## ------------------------------- ##


# -------------------------------- #
# 4b. C compiler characteristics.  #
# -------------------------------- #

# _AC_PROG_CC_C89 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
# ----------------------------------------------------------------
# If the C compiler is not in ANSI C89 (ISO C90) mode by default, try
# to add an option to output variable CC to make it so.  This macro
# tries various options that select ANSI C89 on some system or
# another.  It considers the compiler to be in ANSI C89 mode if it
# handles function prototypes correctly.
AC_DEFUN([_AC_PROG_CC_C89],
[_AC_C_STD_TRY([c89],
[[#include <stdarg.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
struct buf { int x; };
FILE * (*rcsopen) (struct buf *, struct stat *, int);
static char *e (p, i)
     char **p;
     int i;
{
  return p[i];
}
static char *f (char * (*g) (char **, int), char **p, ...)
{
  char *s;
  va_list v;
  va_start (v,p);
  s = g (p, va_arg (v,int));
  va_end (v);
  return s;
}

/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
   function prototypes and stuff, but not '\xHH' hex character constants.
   These don't provoke an error unfortunately, instead are silently treated
   as 'x'.  The following induces an error, until -std is added to get
   proper ANSI mode.  Curiously '\x00'!='x' always comes out true, for an
   array size at least.  It's necessary to write '\x00'==0 to get something
   that's true only with -std.  */
int osf4_cc_array ['\x00' == 0 ? 1 : -1];

/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
   inside strings and character constants.  */
#define FOO(x) 'x'
int xlc6_cc_array[FOO(a) == 'x' ? 1 : -1];

int test (int i, double x);
struct s1 {int (*f) (int a);};
struct s2 {int (*f) (double a);};
int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
int argc;
char **argv;]],
[[return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];]],
dnl Don't try gcc -ansi; that turns off useful extensions and
dnl breaks some systems' header files.
dnl AIX circa 2003	-qlanglvl=extc89
dnl old AIX		-qlanglvl=ansi
dnl Ultrix, OSF/1, Tru64	-std
dnl HP-UX 10.20 and later	-Ae
dnl HP-UX older versions	-Aa -D_HPUX_SOURCE
dnl SVR4			-Xc -D__EXTENSIONS__
[-qlanglvl=extc89 -qlanglvl=ansi -std \
	-Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"], [$1], [$2])[]dnl
])# _AC_PROG_CC_C89


# _AC_C_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
#		ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
# --------------------------------------------------------------
# Check whether the C compiler accepts features of STANDARD (e.g `c89', `c99')
# by trying to compile a program of TEST-PROLOGUE and TEST-BODY.  If this fails,
# try again with each compiler option in the space-separated OPTION-LIST; if one
# helps, append it to CC.  If eventually successful, run ACTION-IF-AVAILABLE,
# else ACTION-IF-UNAVAILABLE.
AC_DEFUN([_AC_C_STD_TRY],
[AC_MSG_CHECKING([for $CC option to accept ISO ]m4_translit($1, [c], [C]))
AC_CACHE_VAL(ac_cv_prog_cc_$1,
[ac_cv_prog_cc_$1=no
ac_save_CC=$CC
AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
for ac_arg in '' $4
do
  CC="$ac_save_CC $ac_arg"
  _AC_COMPILE_IFELSE([], [ac_cv_prog_cc_$1=$ac_arg])
  test "x$ac_cv_prog_cc_$1" != "xno" && break
done
rm -f conftest.$ac_ext
CC=$ac_save_CC
])# AC_CACHE_VAL
case "x$ac_cv_prog_cc_$1" in
  x)
    AC_MSG_RESULT([none needed]) ;;
  xno)
    AC_MSG_RESULT([unsupported]) ;;
  *)
    CC="$CC $ac_cv_prog_cc_$1"
    AC_MSG_RESULT([$ac_cv_prog_cc_$1]) ;;
esac
AS_IF([test "x$ac_cv_prog_cc_$1" != xno], [$5], [$6])
])# _AC_C_STD_TRY


# _AC_PROG_CC_C99 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
# ----------------------------------------------------------------
# If the C compiler is not in ISO C99 mode by default, try to add an
# option to output variable CC to make it so.  This macro tries
# various options that select ISO C99 on some system or another.  It
# considers the compiler to be in ISO C99 mode if it handles mixed
# code and declarations, _Bool, inline and restrict.
AC_DEFUN([_AC_PROG_CC_C99],
[_AC_C_STD_TRY([c99],
[[#include <stdarg.h>
#include <stdbool.h>
#include <stdlib.h>
#include <wchar.h>
#include <stdio.h>

struct incomplete_array
{
  int datasize;
  double data[];
};

struct named_init {
  int number;
  const wchar_t *name;
  double average;
};

typedef const char *ccp;

static inline int
test_restrict(ccp restrict text)
{
  // See if C++-style comments work.
  // Iterate through items via the restricted pointer.
  // Also check for declarations in for loops.
  for (unsigned int i = 0; *(text+i) != '\0'; ++i)
    continue;
  return 0;
}

// Check varargs and va_copy work.
static void
test_varargs(const char *format, ...)
{
  va_list args;
  va_start(args, format);
  va_list args_copy;
  va_copy(args_copy, args);

  const char *str;
  int number;
  float fnumber;

  while (*format)
    {
      switch (*format++)
	{
	case 's': // string
	  str = va_arg(args_copy, const char *);
	  break;
	case 'd': // int
	  number = va_arg(args_copy, int);
	  break;
	case 'f': // float
	  fnumber = (float) va_arg(args_copy, double);
	  break;
	default:
	  break;
	}
    }
  va_end(args_copy);
  va_end(args);
}
]],
[[
  // Check bool and long long datatypes.
  _Bool success = false;
  long long int bignum = -1234567890LL;
  unsigned long long int ubignum = 1234567890uLL;

  // Check restrict.
  if (test_restrict("String literal") != 0)
    success = true;
  char *restrict newvar = "Another string";

  // Check varargs.
  test_varargs("s, d' f .", "string", 65, 34.234);

  // Check incomplete arrays work.
  struct incomplete_array *ia =
    malloc(sizeof(struct incomplete_array) + (sizeof(double) * 10));
  ia->datasize = 10;
  for (int i = 0; i < ia->datasize; ++i)
    ia->data[i] = (double) i * 1.234;

  // Check named initialisers.
  struct named_init ni = {
    .number = 34,
    .name = L"Test wide string",
    .average = 543.34343,
  };

  ni.number = 58;

  int dynamic_array[ni.number];
  dynamic_array[43] = 543;

  // work around unused variable warnings
  return  bignum == 0LL || ubignum == 0uLL || newvar[0] == 'x';
]],
dnl Try
dnl GCC		-std=gnu99 (unused restrictive modes: -std=c99 -std=iso9899:1999)
dnl AIX		-qlanglvl=extc99 (unused restrictive mode: -qlanglvl=stdc99)
dnl Intel ICC	-c99
dnl IRIX	-c99
dnl Solaris	(unused because it causes the compiler to assume C99 semantics for
dnl		library functions, and this is invalid before Solaris 10: -xc99)
dnl Tru64	-c99
dnl with extended modes being tried first.
[[-std=gnu99 -c99 -qlanglvl=extc99]], [$1], [$2])[]dnl
])# _AC_PROG_CC_C99


# AC_PROG_CC_C89
# --------------
AC_DEFUN([AC_PROG_CC_C89],
[ AC_REQUIRE([AC_PROG_CC])dnl
  _AC_PROG_CC_C89
])


# AC_PROG_CC_C99
# --------------
AC_DEFUN([AC_PROG_CC_C99],
[ AC_REQUIRE([AC_PROG_CC])dnl
  _AC_PROG_CC_C99
])


# AC_PROG_CC_STDC
# ---------------
AC_DEFUN([AC_PROG_CC_STDC],
[ AC_REQUIRE([AC_PROG_CC])dnl
  AS_CASE([$ac_cv_prog_cc_stdc],
    [no], [ac_cv_prog_cc_c99=no; ac_cv_prog_cc_c89=no],
	  [_AC_PROG_CC_C99([ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c99],
	     [_AC_PROG_CC_C89([ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c89],
			      [ac_cv_prog_cc_stdc=no])])])dnl
  AC_MSG_CHECKING([for $CC option to accept ISO Standard C])
  AC_CACHE_VAL([ac_cv_prog_cc_stdc], [])
  AS_CASE([$ac_cv_prog_cc_stdc],
    [no], [AC_MSG_RESULT([unsupported])],
    [''], [AC_MSG_RESULT([none needed])],
          [AC_MSG_RESULT([$ac_cv_prog_cc_stdc])])
])


# AC_C_BACKSLASH_A
# ----------------
AC_DEFUN([AC_C_BACKSLASH_A],
[
  AC_CACHE_CHECK([whether backslash-a works in strings], ac_cv_c_backslash_a,
   [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],
     [[
#if '\a' == 'a'
      syntax error;
#endif
      char buf['\a' == 'a' ? -1 : 1];
      buf[0] = '\a';
      return buf[0] != "\a"[0];
     ]])],
     [ac_cv_c_backslash_a=yes],
     [ac_cv_c_backslash_a=no])])
  if test $ac_cv_c_backslash_a = yes; then
    AC_DEFINE(HAVE_C_BACKSLASH_A, 1,
      [Define if backslash-a works in C strings.])
  fi
])


# AC_C_CROSS
# ----------
# Has been merged into AC_PROG_CC.
AU_DEFUN([AC_C_CROSS], [])


# AC_C_CHAR_UNSIGNED
# ------------------
AC_DEFUN([AC_C_CHAR_UNSIGNED],
[AH_VERBATIM([__CHAR_UNSIGNED__],
[/* Define to 1 if type `char' is unsigned and you are not using gcc.  */
#ifndef __CHAR_UNSIGNED__
# undef __CHAR_UNSIGNED__
#endif])dnl
AC_CACHE_CHECK(whether char is unsigned, ac_cv_c_char_unsigned,
[AC_COMPILE_IFELSE([AC_LANG_BOOL_COMPILE_TRY([AC_INCLUDES_DEFAULT([])],
					     [((char) -1) < 0])],
		   ac_cv_c_char_unsigned=no, ac_cv_c_char_unsigned=yes)])
if test $ac_cv_c_char_unsigned = yes && test "$GCC" != yes; then
  AC_DEFINE(__CHAR_UNSIGNED__)
fi
])# AC_C_CHAR_UNSIGNED


# AC_C_BIGENDIAN ([ACTION-IF-TRUE], [ACTION-IF-FALSE], [ACTION-IF-UNKNOWN])
# -------------------------------------------------------------------------
AC_DEFUN([AC_C_BIGENDIAN],
[AC_CACHE_CHECK(whether byte ordering is bigendian, ac_cv_c_bigendian,
[# See if sys/param.h defines the BYTE_ORDER macro.
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <sys/types.h>
#include <sys/param.h>
],
[#if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN
 bogus endian macros
#endif
])],
[# It does; now see whether it defined to BIG_ENDIAN or not.
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <sys/types.h>
#include <sys/param.h>
], [#if BYTE_ORDER != BIG_ENDIAN
 not big endian
#endif
])], [ac_cv_c_bigendian=yes], [ac_cv_c_bigendian=no])],
[# It does not; compile a test program.
AC_RUN_IFELSE(
[AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT], [[
  /* Are we little or big endian?  From Harbison&Steele.  */
  union
  {
    long int l;
    char c[sizeof (long int)];
  } u;
  u.l = 1;
  return u.c[sizeof (long int) - 1] == 1;
]])],
	      [ac_cv_c_bigendian=no],
	      [ac_cv_c_bigendian=yes],
[# try to guess the endianness by grepping values into an object file
  ac_cv_c_bigendian=unknown
  AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
[[short int ascii_mm[] = { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 };
short int ascii_ii[] = { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 };
void _ascii () { char *s = (char *) ascii_mm; s = (char *) ascii_ii; }
short int ebcdic_ii[] = { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 };
short int ebcdic_mm[] = { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 };
void _ebcdic () { char *s = (char *) ebcdic_mm; s = (char *) ebcdic_ii; }]],
[[ _ascii (); _ebcdic (); ]])],
[if grep BIGenDianSyS conftest.$ac_objext >/dev/null ; then
  ac_cv_c_bigendian=yes
fi
if grep LiTTleEnDian conftest.$ac_objext >/dev/null ; then
  if test "$ac_cv_c_bigendian" = unknown; then
    ac_cv_c_bigendian=no
  else
    # finding both strings is unlikely to happen, but who knows?
    ac_cv_c_bigendian=unknown
  fi
fi])])])])
case $ac_cv_c_bigendian in
  yes)
    m4_default([$1],
      [AC_DEFINE([WORDS_BIGENDIAN], 1,
	[Define to 1 if your processor stores words with the most significant
	 byte first (like Motorola and SPARC, unlike Intel and VAX).])]) ;;
  no)
    $2 ;;
  *)
    m4_default([$3],
      [AC_MSG_ERROR([unknown endianness
presetting ac_cv_c_bigendian=no (or yes) will help])]) ;;
esac
])# AC_C_BIGENDIAN


# AC_C_INLINE
# -----------
# Do nothing if the compiler accepts the inline keyword.
# Otherwise define inline to __inline__ or __inline if one of those work,
# otherwise define inline to be empty.
#
# HP C version B.11.11.04 doesn't allow a typedef as the return value for an
# inline function, only builtin types.
#
AN_IDENTIFIER([inline], [AC_C_INLINE])
AC_DEFUN([AC_C_INLINE],
[AC_CACHE_CHECK([for inline], ac_cv_c_inline,
[ac_cv_c_inline=no
for ac_kw in inline __inline__ __inline; do
  AC_COMPILE_IFELSE([AC_LANG_SOURCE(
[#ifndef __cplusplus
typedef int foo_t;
static $ac_kw foo_t static_foo () {return 0; }
$ac_kw foo_t foo () {return 0; }
#endif
])],
		    [ac_cv_c_inline=$ac_kw])
  test "$ac_cv_c_inline" != no && break
done
])
AH_VERBATIM([inline],
[/* Define to `__inline__' or `__inline' if that's what the C compiler
   calls it, or to nothing if 'inline' is not supported under any name.  */
#ifndef __cplusplus
#undef inline
#endif])
case $ac_cv_c_inline in
  inline | yes) ;;
  *)
    case $ac_cv_c_inline in
      no) ac_val=;;
      *) ac_val=$ac_cv_c_inline;;
    esac
    cat >>confdefs.h <<_ACEOF
#ifndef __cplusplus
#define inline $ac_val
#endif
_ACEOF
    ;;
esac
])# AC_C_INLINE


# AC_C_CONST
# ----------
AN_IDENTIFIER([const],  [AC_C_CONST])
AC_DEFUN([AC_C_CONST],
[AC_CACHE_CHECK([for an ANSI C-conforming const], ac_cv_c_const,
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],
[[/* FIXME: Include the comments suggested by Paul. */
#ifndef __cplusplus
  /* Ultrix mips cc rejects this.  */
  typedef int charset[2];
  const charset x;
  /* SunOS 4.1.1 cc rejects this.  */
  char const *const *ccp;
  char **p;
  /* NEC SVR4.0.2 mips cc rejects this.  */
  struct point {int x, y;};
  static struct point const zero = {0,0};
  /* AIX XL C 1.02.0.0 rejects this.
     It does not let you subtract one const X* pointer from another in
     an arm of an if-expression whose if-part is not a constant
     expression */
  const char *g = "string";
  ccp = &g + (g ? g-g : 0);
  /* HPUX 7.0 cc rejects these. */
  ++ccp;
  p = (char**) ccp;
  ccp = (char const *const *) p;
  { /* SCO 3.2v4 cc rejects this.  */
    char *t;
    char const *s = 0 ? (char *) 0 : (char const *) 0;

    *t++ = 0;
    if (s) return 0;
  }
  { /* Someone thinks the Sun supposedly-ANSI compiler will reject this.  */
    int x[] = {25, 17};
    const int *foo = &x[0];
    ++foo;
  }
  { /* Sun SC1.0 ANSI compiler rejects this -- but not the above. */
    typedef const int *iptr;
    iptr p = 0;
    ++p;
  }
  { /* AIX XL C 1.02.0.0 rejects this saying
       "k.c", line 2.27: 1506-025 (S) Operand must be a modifiable lvalue. */
    struct s { int j; const int *ap[3]; };
    struct s *b; b->j = 5;
  }
  { /* ULTRIX-32 V3.1 (Rev 9) vcc rejects this */
    const int foo = 10;
    if (!foo) return 0;
  }
  return !x[0] && !zero.x;
#endif
]])],
		   [ac_cv_c_const=yes],
		   [ac_cv_c_const=no])])
if test $ac_cv_c_const = no; then
  AC_DEFINE(const,,
	    [Define to empty if `const' does not conform to ANSI C.])
fi
])# AC_C_CONST


# AC_C_RESTRICT
# -------------
# based on acx_restrict.m4, from the GNU Autoconf Macro Archive at:
# http://autoconf-archive.cryp.to/acx_restrict.html
#
# Determine whether the C/C++ compiler supports the "restrict" keyword
# introduced in ANSI C99, or an equivalent.  Do nothing if the compiler
# accepts it.  Otherwise, if the compiler supports an equivalent,
# define "restrict" to be that.  Here are some variants:
# - GCC supports both __restrict and __restrict__
# - older DEC Alpha C compilers support only __restrict
# - _Restrict is the only spelling accepted by Sun WorkShop 6 update 2 C
# Otherwise, define "restrict" to be empty.
AN_IDENTIFIER([restrict], [AC_C_RESTRICT])
AC_DEFUN([AC_C_RESTRICT],
[AC_CACHE_CHECK([for C/C++ restrict keyword], ac_cv_c_restrict,
  [ac_cv_c_restrict=no
   # Try the official restrict keyword, then gcc's __restrict, and
   # the less common variants.
   for ac_kw in restrict __restrict __restrict__ _Restrict; do
     AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
      [[typedef int * int_ptr;
        int foo (int_ptr $ac_kw ip) {
        return ip[0];
       }]],
      [[int s[1];
        int * $ac_kw t = s;
        t[0] = 0;
        return foo(t)]])],
      [ac_cv_c_restrict=$ac_kw])
     test "$ac_cv_c_restrict" != no && break
   done
  ])
 case $ac_cv_c_restrict in
   restrict) ;;
   no) AC_DEFINE(restrict,,
	[Define to equivalent of C99 restrict keyword, or to nothing if this
	is not supported.  Do not define if restrict is supported directly.]) ;;
   *)  AC_DEFINE_UNQUOTED(restrict, $ac_cv_c_restrict) ;;
 esac
])# AC_C_RESTRICT


# AC_C_VOLATILE
# -------------
# Note that, unlike const, #defining volatile to be the empty string can
# actually turn a correct program into an incorrect one, since removing
# uses of volatile actually grants the compiler permission to perform
# optimizations that could break the user's code.  So, do not #define
# volatile away unless it is really necessary to allow the user's code
# to compile cleanly.  Benign compiler failures should be tolerated.
AN_IDENTIFIER([volatile], [AC_C_VOLATILE])
AC_DEFUN([AC_C_VOLATILE],
[AC_CACHE_CHECK([for working volatile], ac_cv_c_volatile,
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [
volatile int x;
int * volatile y = (int *) 0;
return !x && !y;])],
		   [ac_cv_c_volatile=yes],
		   [ac_cv_c_volatile=no])])
if test $ac_cv_c_volatile = no; then
  AC_DEFINE(volatile,,
	    [Define to empty if the keyword `volatile' does not work.
	     Warning: valid code using `volatile' can become incorrect
	     without.  Disable with care.])
fi
])# AC_C_VOLATILE


# AC_C_STRINGIZE
# --------------
# Checks if `#' can be used to glue strings together at the CPP level.
# Defines HAVE_STRINGIZE if positive.
AC_DEFUN([AC_C_STRINGIZE],
[AC_CACHE_CHECK([for preprocessor stringizing operator],
		[ac_cv_c_stringize],
[AC_EGREP_CPP([@%:@teststring],
	      [@%:@define x(y) #y

char *s = x(teststring);],
	      [ac_cv_c_stringize=no],
	      [ac_cv_c_stringize=yes])])
if test $ac_cv_c_stringize = yes; then
  AC_DEFINE(HAVE_STRINGIZE, 1,
	    [Define to 1 if cpp supports the ANSI @%:@ stringizing operator.])
fi
])# AC_C_STRINGIZE


# AC_C_PROTOTYPES
# ---------------
# Check if the C compiler supports prototypes, included if it needs
# options.
AC_DEFUN([AC_C_PROTOTYPES],
[AC_REQUIRE([AC_PROG_CC])dnl
AC_MSG_CHECKING([for function prototypes])
if test "$ac_cv_prog_cc_c89" != no; then
  AC_MSG_RESULT([yes])
  AC_DEFINE(PROTOTYPES, 1,
	    [Define to 1 if the C compiler supports function prototypes.])
  AC_DEFINE(__PROTOTYPES, 1,
	    [Define like PROTOTYPES; this can be used by system headers.])
else
  AC_MSG_RESULT([no])
fi
])# AC_C_PROTOTYPES


# AC_C_TYPEOF
# -----------
# Check if the C compiler supports GCC's typeof syntax.
# The test case provokes incompatibilities in the Sun C compilers
# (both Solaris 8 and Solaris 10).
AC_DEFUN([AC_C_TYPEOF],
[
  AC_CACHE_CHECK([for typeof syntax and keyword spelling], ac_cv_c_typeof,
    [ac_cv_c_typeof=no
     for ac_kw in typeof __typeof__ no; do
       test $ac_kw = no && break
       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],
	 [[
	   int value;
	   typedef struct {
		   char a [1
			   + ! (($ac_kw (value))
				(($ac_kw (value)) 0 < ($ac_kw (value)) -1
				 ? ($ac_kw (value)) - 1
				 : ~ (~ ($ac_kw (value)) 0
				      << sizeof ($ac_kw (value)))))]; }
	      ac__typeof_type_;
	   return
	     (! ((void) ((ac__typeof_type_ *) 0), 0));
	 ]])],
	 [ac_cv_c_typeof=$ac_kw])
       test $ac_cv_c_typeof != no && break
     done])
  if test $ac_cv_c_typeof != no; then
    AC_DEFINE([HAVE_TYPEOF], 1,
      [Define to 1 if typeof works with your compiler.])
    if test $ac_cv_c_typeof != typeof; then
      AC_DEFINE_UNQUOTED([typeof], [$ac_cv_c_typeof],
	[Define to __typeof__ if your compiler spells it that way.])
    fi
  fi
])
