##### 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_WARN([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_WARN([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_WARN([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=`$PYTHON -c "from distutils.sysconfig import *; \
			from string import join; \
			print '-L' + get_python_lib(0,1), \
		      	'-lpython';"`$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(0,0);"`
	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_WARN([
  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"
  ============================================================================
   You probably have to install the development version of the Python package
   for your distribution.  The exact name of this package varies among them.

   For example, in Debian and Ubuntu, you would install the python-dev package

  ============================================================================
	   ])
	  PYTHON_VERSION=""
	fi
	AC_LANG_POP
	# turn back to default flags
	CPPFLAGS="$ac_save_CPPFLAGS"
	LIBS="$ac_save_LIBS"

	#
	# all done!
	#
])
