dnl @synopsis AC_PYTHON_DEVEL([version])
  dnl
  dnl Note: Defines as a precious variable "PYTHON_VERSION". Don't
  dnl override it in your configure.ac.
  dnl
  dnl This macro checks for Python and tries to get the include path to
  dnl 'Python.h'. It provides the $(PYTHON_CPPFLAGS) and
  dnl $(PYTHON_LDFLAGS) output variables. It also exports
  dnl $(PYTHON_EXTRA_LIBS) and $(PYTHON_EXTRA_LDFLAGS) for embedding
  dnl Python in your code.
  dnl
  dnl You can search for some particular version of Python by passing a
  dnl parameter to this macro, for example ">= '2.3.1'", or "== '2.4'".
  dnl Please note that you *have* to pass also an operator along with the
  dnl version to match, and pay special attention to the single quotes
  dnl surrounding the version number. Don't use "PYTHON_VERSION" for
  dnl this: that environment variable is declared as precious and thus
  dnl reserved for the end-user.
  dnl
  dnl This macro should work for all versions of Python >= 2.1.0. As an
  dnl end user, you can disable the check for the python version by
  dnl setting the PYTHON_NOVERSIONCHECK environment variable to something
  dnl else than the empty string.
  dnl
  dnl If you need to use this macro for an older Python version, please
  dnl contact the authors. We're always open for feedback.
  dnl
  dnl @category InstalledPackages
  dnl @author Sebastian Huber <sebastian-huber@web.de>
  dnl @author Alan W. Irwin <irwin@beluga.phys.uvic.ca>
  dnl @author Rafael Laboissiere <laboissiere@psy.mpg.de>
  dnl @author Andrew Collier <colliera@nu.ac.za>
  dnl @author Matteo Settenvini <matteo@member.fsf.org>
  dnl @author Horst Knorr <hk_classes@knoda.org>
  dnl @version 2006-05-27
  dnl @license GPLWithACException
  
  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=`$PYTHON -c "from distutils.sysconfig import *; \
  			from string import join; \
  			print '-L' + get_python_lib(0,1), \
  		      	'-lpython';"`$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 ! "$pythonexists" = "yes"; then
  	   AC_MSG_ERROR([
    Could not link test program to Python. Maybe the main Python library has been
    installed in some non-standard library path. If so, pass it to configure,
    via the LDFLAGS environment variable.
    Example: ./configure LDFLAGS="-L/usr/non-standard-path/python/lib"
    ============================================================================
     ERROR!
     You probably have to install the development version of the Python package
     for your distribution.  The exact name of this package varies among them.
    ============================================================================
  	   ])
  	  PYTHON_VERSION=""
  	fi
  	AC_LANG_POP
  	# turn back to default flags
  	CPPFLAGS="$ac_save_CPPFLAGS"
  	LIBS="$ac_save_LIBS"
  
  	#
  	# all done!
  	#
  ])