##### http://autoconf-archive.cryp.to/ac_python_devel.html
#
# SYNOPSIS
#
#   AC_PYTHON_DEVEL([version])
#
# DESCRIPTION
#
#   Note: Defines as a precious variable "PYTHON_VERSION". Don't
#   override it in your configure.ac.
#
#   This macro checks for Python and tries to get the include path to
#   'Python.h'. It provides the $(PYTHON_CPPFLAGS) and
#   $(PYTHON_LDFLAGS) output variables. It also exports
#   $(PYTHON_EXTRA_LIBS) and $(PYTHON_EXTRA_LDFLAGS) for embedding
#   Python in your code.
#
#   You can search for some particular version of Python by passing a
#   parameter to this macro, for example ">= '2.3.1'", or "== '2.4'".
#   Please note that you *have* to pass also an operator along with the
#   version to match, and pay special attention to the single quotes
#   surrounding the version number. Don't use "PYTHON_VERSION" for
#   this: that environment variable is declared as precious and thus
#   reserved for the end-user.
#
#   This macro should work for all versions of Python >= 2.1.0. As an
#   end user, you can disable the check for the python version by
#   setting the PYTHON_NOVERSIONCHECK environment variable to something
#   else than the empty string.
#
#   If you need to use this macro for an older Python version, please
#   contact the authors. We're always open for feedback.
#
# 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>
#   Copyright (c) 2006 Matteo Settenvini <matteo@member.fsf.org>
#   Copyright (c) 2006 Horst Knorr <hk_classes@knoda.org>
#
#   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_PYTHON_DEVEL],[
	#
	# Allow the use of a (user set) custom python version
	#
	AC_ARG_VAR([PYTHON_VERSION],[The installed Python
		version to use, for example '2.3'. This string
		will be appended to the Python interpreter
		canonical name.])

	AC_PATH_PROG([PYTHON],[python[$PYTHON_VERSION]])
	if test -z "$PYTHON"; then
	   AC_MSG_ERROR([Cannot find python$PYTHON_VERSION in your system path])
	   PYTHON_VERSION=""
	fi

	#
	# Check for a version of Python >= 2.1.0
	#
	AC_MSG_CHECKING([for a version of Python >= '2.1.0'])
	ac_supports_python_ver=`$PYTHON -c "import sys, string; \
		ver = string.split(sys.version)[[0]]; \
		print ver >= '2.1.0'"`
	if test "$ac_supports_python_ver" != "True"; then
		if test -z "$PYTHON_NOVERSIONCHECK"; then
			AC_MSG_RESULT([no])
			AC_MSG_FAILURE([
This version of the AC@&t@_PYTHON_DEVEL macro
doesn't work properly with versions of Python before
2.1.0. You may need to re-run configure, setting the
variables PYTHON_CPPFLAGS, PYTHON_LDFLAGS, PYTHON_SITE_PKG,
PYTHON_EXTRA_LIBS and PYTHON_EXTRA_LDFLAGS by hand.
Moreover, to disable this check, set PYTHON_NOVERSIONCHECK
to something else than an empty string.
])
		else
			AC_MSG_RESULT([skip at user request])
		fi
	else
		AC_MSG_RESULT([yes])
	fi

	#
	# if the macro parameter ``version'' is set, honour it
	#
	if test -n "$1"; then
		AC_MSG_CHECKING([for a version of Python $1])
		ac_supports_python_ver=`$PYTHON -c "import sys, string; \
			ver = string.split(sys.version)[[0]]; \
			print ver $1"`
		if test "$ac_supports_python_ver" = "True"; then
	   	   AC_MSG_RESULT([yes])
		else
			AC_MSG_RESULT([no])
			AC_MSG_ERROR([this package requires Python $1.
If you have it installed, but it isn't the default Python
interpreter in your system path, please pass the PYTHON_VERSION
variable to configure. See ``configure --help'' for reference.
])
			PYTHON_VERSION=""
		fi
	fi

	#
	# Check if you have distutils, else fail
	#
	AC_MSG_CHECKING([for the distutils Python package])
	ac_distutils_result=`$PYTHON -c "import distutils" 2>&1`
	if test -z "$ac_distutils_result"; then
		AC_MSG_RESULT([yes])
	else
		AC_MSG_RESULT([no])
		AC_MSG_ERROR([cannot import Python module "distutils".
Please check your Python installation. The error was:
$ac_distutils_result])
		PYTHON_VERSION=""
	fi

	#
	# Check for Python include path
	#
	AC_MSG_CHECKING([for Python include path])
	if test -z "$PYTHON_CPPFLAGS"; then
		python_path=`$PYTHON -c "import distutils.sysconfig; \
           		print distutils.sysconfig.get_python_inc();"`
		if test -n "${python_path}"; then
		   	python_path="-I$python_path"
		fi
		PYTHON_CPPFLAGS=$python_path
	fi
	AC_MSG_RESULT([$PYTHON_CPPFLAGS])
	AC_SUBST([PYTHON_CPPFLAGS])

	#
	# Check for Python library path
	#
	AC_MSG_CHECKING([for Python library path])
	if test -z "$PYTHON_LDFLAGS"; then
		# (makes two attempts to ensure we've got a version number
		# from the interpreter)
		py_version=`$PYTHON -c "from distutils.sysconfig import *; \
			from string import join; \
			print join(get_config_vars('VERSION'))"`
		if test "$py_version" == "[None]"; then
			if test -n "$PYTHON_VERSION"; then
				py_version=$PYTHON_VERSION
			else
				py_version=`$PYTHON -c "import sys; \
					print sys.version[[:3]]"`
			fi
		fi

		PYTHON_LDFLAGS=`$PYTHON -c "from distutils.sysconfig import *; \
			from string import join; \
			print '-L' + get_python_lib(1,1), \
		      	'-lpython';"`$py_version
	fi
	AC_MSG_RESULT([$PYTHON_LDFLAGS])
	AC_SUBST([PYTHON_LDFLAGS])

	#
	# Check for site packages
	#
	AC_MSG_CHECKING([for Python site-packages path])
	if test -z "$PYTHON_SITE_PKG"; then
		PYTHON_SITE_PKG=`$PYTHON -c "import distutils.sysconfig; \
		        print distutils.sysconfig.get_python_lib(1,0);"`
	fi
	AC_MSG_RESULT([$PYTHON_SITE_PKG])
	AC_SUBST([PYTHON_SITE_PKG])

	#
	# libraries which must be linked in when embedding
	#
	AC_MSG_CHECKING(python extra libraries)
	if test -z "$PYTHON_EXTRA_LIBS"; then
	   PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
                conf = distutils.sysconfig.get_config_var; \
                print conf('LOCALMODLIBS'), conf('LIBS')"`
	fi
	AC_MSG_RESULT([$PYTHON_EXTRA_LIBS])
	AC_SUBST(PYTHON_EXTRA_LIBS)

	#
	# linking flags needed when embedding
	#
	AC_MSG_CHECKING(python extra linking flags)
	if test -z "$PYTHON_EXTRA_LDFLAGS"; then
		PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "import distutils.sysconfig; \
			conf = distutils.sysconfig.get_config_var; \
			print conf('LINKFORSHARED')"`
	fi
	AC_MSG_RESULT([$PYTHON_EXTRA_LDFLAGS])
	AC_SUBST(PYTHON_EXTRA_LDFLAGS)

	#
	# final check to see if everything compiles alright
	#
	AC_MSG_CHECKING([consistency of all components of python development environment])
	AC_LANG_PUSH([C])
	# save current global flags
	LIBS="$ac_save_LIBS $PYTHON_LDFLAGS"
	CPPFLAGS="$ac_save_CPPFLAGS $PYTHON_CPPFLAGS"
	AC_TRY_LINK([
		#include <Python.h>
	],[
		Py_Initialize();
	],[pythonexists=yes],[pythonexists=no])

	AC_MSG_RESULT([$pythonexists])

        if test ! "$pythonexists" = "yes"; then
	   AC_MSG_ERROR([
  Could not link test program to Python. Maybe the main Python library has been
  installed in some non-standard library path. If so, pass it to configure,
  via the LDFLAGS environment variable.
  Example: ./configure LDFLAGS="-L/usr/non-standard-path/python/lib"
  ============================================================================
   ERROR!
   You probably have to install the development version of the Python package
   for your distribution.  The exact name of this package varies among them.
  ============================================================================
	   ])
	  PYTHON_VERSION=""
	fi
	AC_LANG_POP
	# turn back to default flags
	CPPFLAGS="$ac_save_CPPFLAGS"
	LIBS="$ac_save_LIBS"

	#
	# all done!
	#
])