##### http://autoconf-archive.cryp.to/ac_pkg_swig.html
#
# SYNOPSIS
#
#   AC_PROG_SWIG([major.minor.micro])
#
# DESCRIPTION
#
#   This macro searches for a SWIG installation on your system. If
#   found you should call SWIG via $(SWIG). You can use the optional
#   first argument to check if the version of the available SWIG is
#   greater than or equal to the value of the argument. It should have
#   the format: N[.N[.N]] (N is a number between 0 and 999. Only the
#   first N is mandatory.)
#
#   If the version argument is given (e.g. 1.3.17), AC_PROG_SWIG checks
#   that the swig package is this version number or higher.
#
#   In configure.in, use as:
#
#     AC_PROG_SWIG(1.3.17)
#     SWIG_ENABLE_CXX
#     SWIG_MULTI_MODULE_SUPPORT
#     SWIG_PYTHON
#
# LAST MODIFICATION
#
#   2006-10-22
#
# COPYLEFT
#
#   Copyright (c) 2006 Sebastian Huber <sebastian-huber@web.de>
#   Copyright (c) 2006 Alan W. Irwin <irwin@beluga.phys.uvic.ca>
#   Copyright (c) 2006 Rafael Laboissiere <rafael@laboissiere.net>
#   Copyright (c) 2006 Andrew Collier <colliera@ukzn.ac.za>
#
#   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 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, write to the Free Software
#   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
#   02111-1307, USA.
#
#   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 Macro 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.

AC_DEFUN([AC_PROG_SWIG],[
        AC_PATH_PROG([SWIG],[swig])
        if test -z "$SWIG" ; then
                AC_MSG_WARN([cannot find 'swig' program. You should look at http://www.swig.org])
                SWIG='no'
        elif test -n "$1" ; then
                AC_MSG_CHECKING([for SWIG version])
                [swig_version=`$SWIG -version 2>&1 | grep 'SWIG Version' | sed 's/.*\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\).*/\1/g'`]
                AC_MSG_RESULT([$swig_version])
                if test -n "$swig_version" ; then
                        # Calculate the required version number components
                        [required=$1]
                        [required_major=`echo $required | sed 's/[^0-9].*//'`]
                        if test -z "$required_major" ; then
                                [required_major=0]
                        fi
                        [required=`echo $required | sed 's/[0-9]*[^0-9]//'`]
                        [required_minor=`echo $required | sed 's/[^0-9].*//'`]
                        if test -z "$required_minor" ; then
                                [required_minor=0]
                        fi
                        [required=`echo $required | sed 's/[0-9]*[^0-9]//'`]
                        [required_patch=`echo $required | sed 's/[^0-9].*//'`]
                        if test -z "$required_patch" ; then
                                [required_patch=0]
                        fi
                        # Calculate the available version number components
                        [available=$swig_version]
                        [available_major=`echo $available | sed 's/[^0-9].*//'`]
                        if test -z "$available_major" ; then
                                [available_major=0]
                        fi
                        [available=`echo $available | sed 's/[0-9]*[^0-9]//'`]
                        [available_minor=`echo $available | sed 's/[^0-9].*//'`]
                        if test -z "$available_minor" ; then
                                [available_minor=0]
                        fi
                        [available=`echo $available | sed 's/[0-9]*[^0-9]//'`]
                        [available_patch=`echo $available | sed 's/[^0-9].*//'`]
                        if test -z "$available_patch" ; then
                                [available_patch=0]
                        fi
                        if test $available_major -ne $required_major \
                                -o $available_minor -ne $required_minor \
                                -o $available_patch -lt $required_patch ; then
                                AC_MSG_WARN([SWIG version >= $1 is required.  You have $swig_version.  You should look at http://www.swig.org])
                                SWIG='no'
                        else
                                AC_MSG_NOTICE([SWIG executable is '$SWIG'])
                                SWIG_LIB=`$SWIG -swiglib`
                                AC_MSG_NOTICE([SWIG library directory is '$SWIG_LIB'])
                        fi
                else
                        AC_MSG_WARN([cannot determine SWIG version])
                        SWIG='no'
                fi
        fi
        AC_SUBST([SWIG_LIB])
])