# ===========================================================================

#    http://www.gnu.org/software/autoconf-archive/ax_prefix_config_h.html

# ===========================================================================

#

# SYNOPSIS

#

#   AX_PREFIX_CONFIG_H [(OUTPUT-HEADER [,PREFIX [,ORIG-HEADER]])]

#

# DESCRIPTION

#

#   Generate an installable config.h.

#

#   A package should not normally install its config.h as a system header,

#   but if it must, this macro can be used to avoid namespace pollution by

#   making a copy of config.h with a prefix added to all the macro names.

#

#   Each "#define SOMEDEF" line of the configuration header has the given

#   prefix added, in the same case as the first character of the macro name.

#

#   Defaults:

#

#     OUTPUT-HEADER = $PACKAGE-config.h

#     PREFIX = $PACKAGE

#     ORIG-HEADER, from AM_CONFIG_HEADER(config.h)

#

#   Your configure.ac script should contain both macros in this order.

#

#   Example:

#

#     AC_INIT(config.h.in)        # config.h.in as created by "autoheader"

#     AM_INIT_AUTOMAKE(testpkg, 0.1.1)    # makes #undef VERSION and PACKAGE

#     AM_CONFIG_HEADER(config.h)          # prep config.h from config.h.in

#     AX_PREFIX_CONFIG_H(mylib/_config.h) # prep mylib/_config.h from it..

#     AC_MEMORY_H                         # makes "#undef NEED_MEMORY_H"

#     AC_C_CONST_H                        # makes "#undef const"

#     AC_OUTPUT(Makefile)                 # creates the "config.h" now

#                                         # and also mylib/_config.h

#

#   If the argument to AX_PREFIX_CONFIG_H would have been omitted then the

#   default output file would have been called simply "testpkg-config.h",

#   but even under the name "mylib/_config.h" it contains prefix-defines

#   like

#

#     #ifndef TESTPKG_VERSION

#     #define TESTPKG_VERSION "0.1.1"

#     #endif

#     #ifndef TESTPKG_NEED_MEMORY_H

#     #define TESTPKG_NEED_MEMORY_H 1

#     #endif

#     #ifndef _testpkg_const

#     #define _testpkg_const _const

#     #endif

#

#   and this "mylib/_config.h" can be installed along with other header

#   files, which is most convenient when creating a shared library (that has

#   some headers) whose functionality depends on features detected at

#   compile-time. No need to invent some "mylib-confdefs.h.in" manually.

#

#   Note that some AC_DEFINEs that end up in the config.h file are actually

#   self-referential - e.g. AC_C_INLINE, AC_C_CONST, and the AC_TYPE_OFF_T

#   say that they "will define inline|const|off_t if the system does not do

#   it by itself". You might want to clean up about these - consider an

#   extra mylib/conf.h that reads something like:

#

#     #include <mylib/_config.h>

#     #ifndef _testpkg_const

#     #define _testpkg_const const

#     #endif

#

#   and then start using _testpkg_const in the header files. That is also a

#   good thing to differentiate whether some library-user has starting to

#   take up with a different compiler, so perhaps it could read something

#   like this:

#

#     #ifdef _MSC_VER

#     #include <mylib/_msvc.h>

#     #else

#     #include <mylib/_config.h>

#     #endif

#     #ifndef _testpkg_const

#     #define _testpkg_const const

#     #endif

#

# LICENSE

#

#   Copyright (c) 2014 Reuben Thomas <rrt@sc3d.org>

#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>

#   Copyright (c) 2008 Marten Svantesson

#   Copyright (c) 2008 Gerald Point <Gerald.Point@labri.fr>

#

#   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.

#

#   You should have received a copy of the GNU General Public License along

#   with this program. If not, see <http://www.gnu.org/licenses/>.

#

#   As a special exception, the respective Autoconf Macro's copyright owner

#   gives unlimited permission to copy, distribute and modify the configure

#   scripts that are the output of Autoconf when processing the Macro. 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 the

#   Macro appear in them. The GNU General Public License (GPL) does govern

#   all other use of the material that constitutes the Autoconf Macro.

#

#   This special exception to the GPL applies to versions of the Autoconf

#   Macro released by the Autoconf Archive. When you make and distribute a

#   modified version of the Autoconf Macro, you may extend this special

#   exception to the GPL to apply to your modified version as well.

#serial 15

AC_DEFUN([AX_PREFIX_CONFIG_H],[dnl

AC_PREREQ([2.62])

AC_BEFORE([AC_CONFIG_HEADERS],[$0])dnl

AC_CONFIG_COMMANDS(m4_default([$1], [$PACKAGE-config.h]),[dnl

AS_VAR_PUSHDEF([_OUT],[ac_prefix_conf_OUT])dnl

AS_VAR_PUSHDEF([_DEF],[ac_prefix_conf_DEF])dnl

AS_VAR_PUSHDEF([_PKG],[ac_prefix_conf_PKG])dnl

AS_VAR_PUSHDEF([_LOW],[ac_prefix_conf_LOW])dnl

AS_VAR_PUSHDEF([_UPP],[ac_prefix_conf_UPP])dnl

AS_VAR_PUSHDEF([_INP],[ac_prefix_conf_INP])dnl

m4_pushdef([_script],[conftest.prefix])dnl

m4_pushdef([_symbol],[m4_cr_Letters[]m4_cr_digits[]_])dnl

_OUT=`echo m4_default([$1], [$PACKAGE-config.h])`

_DEF=`echo _$_OUT | sed -e "y:m4_cr_letters:m4_cr_LETTERS[]:" -e "s/@<:@^m4_cr_Letters@:>@/_/g"`

_PKG=`echo m4_default([$2], [$PACKAGE])`

_LOW=`echo _$_PKG | sed -e "y:m4_cr_LETTERS-:m4_cr_letters[]_:"`

_UPP=`echo $_PKG | sed -e "y:m4_cr_letters-:m4_cr_LETTERS[]_:"  -e "/^@<:@m4_cr_digits@:>@/s/^/_/"`

_INP=`echo "$3" | sed -e 's/ *//'`

if test ".$_INP" = "."; then

   for ac_file in : $CONFIG_HEADERS; do test "_$ac_file" = _: && continue

     case "$ac_file" in

        *.h) _INP=$ac_file ;;

        *)

     esac

     test ".$_INP" != "." && break

   done

fi

if test ".$_INP" = "."; then

   case "$_OUT" in

      */*) _INP=`basename "$_OUT"`

      ;;

      *-*) _INP=`echo "$_OUT" | sed -e "s/@<:@_symbol@:>@*-//"`

      ;;

      *) _INP=config.h

      ;;

   esac

fi

if test -z "$_PKG" ; then

   AC_MSG_ERROR([no prefix for _PREFIX_PKG_CONFIG_H])

else

  if test ! -f "$_INP" ; then if test -f "$srcdir/$_INP" ; then

     _INP="$srcdir/$_INP"

  fi fi

  AC_MSG_NOTICE(creating $_OUT - prefix $_UPP for $_INP defines)

  if test -f $_INP ; then

    AS_ECHO(["s/^@%:@undef  *\\(@<:@m4_cr_LETTERS[]_@:>@\\)/@%:@undef $_UPP""_\\1/"]) > _script

    AS_ECHO(["s/^@%:@undef  *\\(@<:@m4_cr_letters@:>@\\)/@%:@undef $_LOW""_\\1/"]) >> _script

    AS_ECHO(["s/^@%:@def[]ine  *\\(@<:@m4_cr_LETTERS[]_@:>@@<:@_symbol@:>@*\\)\\(.*\\)/@%:@ifndef $_UPP""_\\1\\"]) >> _script

    AS_ECHO(["@%:@def[]ine $_UPP""_\\1\\2\\"]) >> _script

    AS_ECHO(["@%:@endif/"]) >> _script

    AS_ECHO(["s/^@%:@def[]ine  *\\(@<:@m4_cr_letters@:>@@<:@_symbol@:>@*\\)\\(.*\\)/@%:@ifndef $_LOW""_\\1\\"]) >> _script

    AS_ECHO(["@%:@define $_LOW""_\\1\\2\\"]) >> _script

    AS_ECHO(["@%:@endif/"]) >> _script

    # now executing _script on _DEF input to create _OUT output file

    echo "@%:@ifndef $_DEF"      >$tmp/pconfig.h

    echo "@%:@def[]ine $_DEF 1" >>$tmp/pconfig.h

    echo ' ' >>$tmp/pconfig.h

    echo /'*' $_OUT. Generated automatically at end of configure. '*'/ >>$tmp/pconfig.h

    sed -f _script $_INP >>$tmp/pconfig.h

    echo ' ' >>$tmp/pconfig.h

    echo '/* once:' $_DEF '*/' >>$tmp/pconfig.h

    echo "@%:@endif" >>$tmp/pconfig.h

    if cmp -s $_OUT $tmp/pconfig.h 2>/dev/null; then

      AC_MSG_NOTICE([$_OUT is unchanged])

    else

      ac_dir=`AS_DIRNAME(["$_OUT"])`

      AS_MKDIR_P(["$ac_dir"])

      rm -f "$_OUT"

      mv $tmp/pconfig.h "$_OUT"

    fi

  else

    AC_MSG_ERROR([input file $_INP does not exist - skip generating $_OUT])

  fi

  rm -f conftest.*

fi

m4_popdef([_symbol])dnl

m4_popdef([_script])dnl

AS_VAR_POPDEF([_INP])dnl

AS_VAR_POPDEF([_UPP])dnl

AS_VAR_POPDEF([_LOW])dnl

AS_VAR_POPDEF([_PKG])dnl

AS_VAR_POPDEF([_DEF])dnl

AS_VAR_POPDEF([_OUT])dnl

],[PACKAGE="$PACKAGE"])])