configure: Clean up Python checking

This fixes requiring to add a version every time
a new release comes out...

1 files changed, 327 insertions, 0 deletions

diff --git a/m4/ax_python_devel.m4 b/m4/ax_python_devel.m4
new file mode 100644
index 00000000..f18ed8a0
--- /dev/null
+++ b/m4/ax_python_devel.m4
@@ -0,0 +1,327 @@
+# ===========================================================================
+#      http://www.gnu.org/software/autoconf-archive/ax_python_devel.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_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_LIBS) 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.
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Sebastian Huber <sebastian-huber@web.de>
+#   Copyright (c) 2009 Alan W. Irwin
+#   Copyright (c) 2009 Rafael Laboissiere <rafael@laboissiere.net>
+#   Copyright (c) 2009 Andrew Collier
+#   Copyright (c) 2009 Matteo Settenvini <matteo@member.fsf.org>
+#   Copyright (c) 2009 Horst Knorr <hk_classes@knoda.org>
+#   Copyright (c) 2013 Daniel Mullner <muellner@math.stanford.edu>
+#
+#   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 18
+
+AU_ALIAS([AC_PYTHON_DEVEL], [AX_PYTHON_DEVEL])
+AC_DEFUN([AX_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=`$PYTHON -c "import sys; \
+		ver = sys.version.split ()[[0]]; \
+		print (ver >= '2.1.0')"`
+	if test "$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_LIBS, 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; \
+			ver = sys.version.split ()[[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 ());"`
+		plat_python_path=`$PYTHON -c "import distutils.sysconfig; \
+			print (distutils.sysconfig.get_python_inc (plat_specific=1));"`
+		if test -n "${python_path}"; then
+			if test "${plat_python_path}" != "${python_path}"; then
+				python_path="-I$python_path -I$plat_python_path"
+			else
+				python_path="-I$python_path"
+			fi
+		fi
+		PYTHON_CPPFLAGS=$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_LIBS"; then
+		# (makes two attempts to ensure we've got a version number
+		# from the interpreter)
+		ac_python_version=`cat<<EOD | $PYTHON -
+
+# join all versioning strings, on some systems
+# major/minor numbers could be in different list elements
+from distutils.sysconfig import *
+e = get_config_var('VERSION')
+if e is not None:
+	print(e)
+EOD`
+
+		if test -z "$ac_python_version"; then
+			if test -n "$PYTHON_VERSION"; then
+				ac_python_version=$PYTHON_VERSION
+			else
+				ac_python_version=`$PYTHON -c "import sys; \
+					print (sys.version[[:3]])"`
+			fi
+		fi
+
+		# Make the versioning information available to the compiler
+		AC_DEFINE_UNQUOTED([HAVE_PYTHON], ["$ac_python_version"],
+                                   [If available, contains the Python version number currently in use.])
+
+		# First, the library directory:
+		ac_python_libdir=`cat<<EOD | $PYTHON -
+
+# There should be only one
+import distutils.sysconfig
+e = distutils.sysconfig.get_config_var('LIBDIR')
+if e is not None:
+	print (e)
+EOD`
+
+		# Now, for the library:
+		ac_python_library=`cat<<EOD | $PYTHON -
+
+import distutils.sysconfig
+c = distutils.sysconfig.get_config_vars()
+if 'LDVERSION' in c:
+	print ('python'+c[['LDVERSION']])
+else:
+	print ('python'+c[['VERSION']])
+EOD`
+
+		# This small piece shamelessly adapted from PostgreSQL python macro;
+		# credits goes to momjian, I think. I'd like to put the right name
+		# in the credits, if someone can point me in the right direction... ?
+		#
+		if test -n "$ac_python_libdir" -a -n "$ac_python_library"
+		then
+			# use the official shared library
+			ac_python_library=`echo "$ac_python_library" | sed "s/^lib//"`
+			PYTHON_LIBS="-L$ac_python_libdir -l$ac_python_library"
+		else
+			# old way: use libpython from python_configdir
+			ac_python_libdir=`$PYTHON -c \
+			  "from distutils.sysconfig import get_python_lib as f; \
+			  import os; \
+			  print (os.path.join(f(plat_specific=1, standard_lib=1), 'config'));"`
+			PYTHON_LIBS="-L$ac_python_libdir -lpython$ac_python_version"
+		fi
+
+		if test -z "PYTHON_LIBS"; then
+			AC_MSG_ERROR([
+  Cannot determine location of your Python DSO. Please check it was installed with
+  dynamic libraries enabled, or try setting PYTHON_LIBS by hand.
+			])
+		fi
+	fi
+	AC_MSG_RESULT([$PYTHON_LIBS])
+	AC_SUBST([PYTHON_LIBS])
+
+	#
+	# 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_LDFLAGS"; then
+	   PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "import distutils.sysconfig; \
+                conf = distutils.sysconfig.get_config_var; \
+                print (conf('LIBS') + ' ' + conf('SYSLIBS'))"`
+	fi
+	AC_MSG_RESULT([$PYTHON_EXTRA_LDFLAGS])
+	AC_SUBST(PYTHON_EXTRA_LDFLAGS)
+
+	#
+	# linking flags needed when embedding
+	#
+	AC_MSG_CHECKING(python extra linking flags)
+	if test -z "$PYTHON_EXTRA_LIBS"; then
+		PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
+			conf = distutils.sysconfig.get_config_var; \
+			print (conf('LINKFORSHARED'))"`
+	fi
+	AC_MSG_RESULT([$PYTHON_EXTRA_LIBS])
+	AC_SUBST(PYTHON_EXTRA_LIBS)
+
+	#
+	# final check to see if everything compiles alright
+	#
+	AC_MSG_CHECKING([consistency of all components of python development environment])
+	# save current global flags
+	ac_save_LIBS="$LIBS"
+	ac_save_LDFLAGS="$LDFLAGS"
+	ac_save_CPPFLAGS="$CPPFLAGS"
+	LIBS="$ac_save_LIBS $PYTHON_LIBS $PYTHON_EXTRA_LIBS $PYTHON_EXTRA_LIBS"
+	LDFLAGS="$ac_save_LDFLAGS $PYTHON_EXTRA_LDFLAGS"
+	CPPFLAGS="$ac_save_CPPFLAGS $PYTHON_CPPFLAGS"
+	AC_LANG_PUSH([C])
+	AC_LINK_IFELSE([
+		AC_LANG_PROGRAM([[#include <Python.h>]],
+				[[Py_Initialize();]])
+		],[pythonexists=yes],[pythonexists=no])
+	AC_LANG_POP([C])
+	# turn back to default flags
+	CPPFLAGS="$ac_save_CPPFLAGS"
+	LIBS="$ac_save_LIBS"
+	LDFLAGS="$ac_save_LDFLAGS"
+
+	AC_MSG_RESULT([$pythonexists])
+
+        if test ! "x$pythonexists" = "xyes"; then
+	   AC_MSG_FAILURE([
+  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 LIBS environment variable.
+  Example: ./configure LIBS="-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
+
+	#
+	# all done!
+	#
+])