Update python configuration, support platform site dir

Update to the most recent ax_python_devel.m4 from autoconf-archive
2022.09.03. It reports two separate directories, one for platform
independent files, another for platform specific files.

Make minimal change and switch to using platform dependent directory.
Should work on python 3.12, which removes distutils module completely.

Makefile.in

@@ -20,7 +20,7 @@ p5_dns_ldns_dir = $(srcdir)/contrib/DNS-LDNS
 PERL		= @PERL@
 swig		= @swig@
 swigpy_flags	= -python @SWIGPY3@
-python_site	= @PYTHON_SITE_PKG@
+python_site	= @PYTHON_PLATFORM_SITE_PKG@
 pyldns_inst	= @PYLDNSINST@
 pyldns_uninst	= @PYLDNSUNINST@
 pyldnsx_inst	= @PYLDNSXINST@

ax_python_devel.m4

@@ -67,7 +67,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 21
+#serial 32
 
 AU_ALIAS([AC_PYTHON_DEVEL], [AX_PYTHON_DEVEL])
 AC_DEFUN([AX_PYTHON_DEVEL],[
@@ -112,15 +112,39 @@ to something else than an empty string.
 	fi
 
 	#
-	# if the macro parameter ``version'' is set, honour it
+	# If the macro parameter ``version'' is set, honour it.
+	# A Python shim class, VPy, is used to implement correct version comparisons via
+	# string expressions, since e.g. a naive textual ">= 2.7.3" won't work for
+	# Python 2.7.10 (the ".1" being evaluated as less than ".3").
 	#
 	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]]; \
+                cat << EOF > ax_python_devel_vpy.py
+class VPy:
+    def vtup(self, s):
+        return tuple(map(int, s.strip().replace("rc", ".").split(".")))
+    def __init__(self):
+        import sys
+        self.vpy = tuple(sys.version_info)
+    def __eq__(self, s):
+        return self.vpy == self.vtup(s)
+    def __ne__(self, s):
+        return self.vpy != self.vtup(s)
+    def __lt__(self, s):
+        return self.vpy < self.vtup(s)
+    def __gt__(self, s):
+        return self.vpy > self.vtup(s)
+    def __le__(self, s):
+        return self.vpy <= self.vtup(s)
+    def __ge__(self, s):
+        return self.vpy >= self.vtup(s)
+EOF
+		ac_supports_python_ver=`$PYTHON -c "import ax_python_devel_vpy; \
+                        ver = ax_python_devel_vpy.VPy(); \
 			print (ver $1)"`
+                rm -rf ax_python_devel_vpy*.py* __pycache__/ax_python_devel_vpy*.py*
 		if test "$ac_supports_python_ver" = "True"; then
-		   AC_MSG_RESULT([yes])
+			AC_MSG_RESULT([yes])
 		else
 			AC_MSG_RESULT([no])
 			AC_MSG_ERROR([this package requires Python $1.
@@ -135,27 +159,45 @@ variable to configure. See ``configure --help'' for reference.
 	#
 	# Check if you have distutils, else fail
 	#
-	AC_MSG_CHECKING([for the distutils Python package])
-	ac_distutils_result=`$PYTHON -c "import distutils" 2>&1`
+	AC_MSG_CHECKING([for the sysconfig Python package])
+	ac_sysconfig_result=`$PYTHON -c "import sysconfig" 2>&1`
 	if test $? -eq 0; then
 		AC_MSG_RESULT([yes])
+		IMPORT_SYSCONFIG="import sysconfig"
 	else
 		AC_MSG_RESULT([no])
-		AC_MSG_ERROR([cannot import Python module "distutils".
+
+		AC_MSG_CHECKING([for the distutils Python package])
+		ac_sysconfig_result=`$PYTHON -c "from distutils import sysconfig" 2>&1`
+		if test $? -eq 0; then
+			AC_MSG_RESULT([yes])
+			IMPORT_SYSCONFIG="from distutils import sysconfig"
+		else
+			AC_MSG_ERROR([cannot import Python module "distutils".
 Please check your Python installation. The error was:
-$ac_distutils_result])
-		PYTHON_VERSION=""
+$ac_sysconfig_result])
+			PYTHON_VERSION=""
+		fi
 	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=`$PYTHON -c "import distutils.sysconfig; \
-			print (distutils.sysconfig.get_python_inc (plat_specific=1));"`
+		if test "$IMPORT_SYSCONFIG" = "import sysconfig"; then
+			# sysconfig module has different functions
+			python_path=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+				print (sysconfig.get_path ('include'));"`
+			plat_python_path=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+				print (sysconfig.get_path ('platinclude'));"`
+		else
+			# old distutils way
+			python_path=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+				print (sysconfig.get_python_inc ());"`
+			plat_python_path=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+				print (sysconfig.get_python_inc (plat_specific=1));"`
+		fi
 		if test -n "${python_path}"; then
 			if test "${plat_python_path}" != "${python_path}"; then
 				python_path="-I$python_path -I$plat_python_path"
@@ -179,7 +221,7 @@ $ac_distutils_result])
 
 # join all versioning strings, on some systems
 # major/minor numbers could be in different list elements
-from distutils.sysconfig import *
+from sysconfig import *
 e = get_config_var('VERSION')
 if e is not None:
 	print(e)
@@ -190,7 +232,7 @@ EOD`
 				ac_python_version=$PYTHON_VERSION
 			else
 				ac_python_version=`$PYTHON -c "import sys; \
-					print (sys.version[[:3]])"`
+					print ("%d.%d" % sys.version_info[[:2]])"`
 			fi
 		fi
 
@@ -202,17 +244,17 @@ EOD`
 		ac_python_libdir=`cat<<EOD | $PYTHON -
 
 # There should be only one
-import distutils.sysconfig
-e = distutils.sysconfig.get_config_var('LIBDIR')
+$IMPORT_SYSCONFIG
+e = 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()
+$IMPORT_SYSCONFIG
+c = sysconfig.get_config_vars()
 if 'LDVERSION' in c:
 	print ('python'+c[['LDVERSION']])
 else:
@@ -231,7 +273,7 @@ EOD`
 		else
 			# old way: use libpython from python_configdir
 			ac_python_libdir=`$PYTHON -c \
-			  "from distutils.sysconfig import get_python_lib as f; \
+			  "from 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"
@@ -252,19 +294,66 @@ EOD`
 	#
 	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));"`
+		if test "$IMPORT_SYSCONFIG" = "import sysconfig"; then
+			PYTHON_SITE_PKG=`$PYTHON -c "
+$IMPORT_SYSCONFIG;
+if hasattr(sysconfig, 'get_default_scheme'):
+    scheme = sysconfig.get_default_scheme()
+else:
+    scheme = sysconfig._get_default_scheme()
+if scheme == 'posix_local':
+    # Debian's default scheme installs to /usr/local/ but we want to find headers in /usr/
+    scheme = 'posix_prefix'
+prefix = '$prefix'
+if prefix == 'NONE':
+    prefix = '$ac_default_prefix'
+sitedir = sysconfig.get_path('purelib', scheme, vars={'base': prefix})
+print(sitedir)"`
+		else
+			# distutils.sysconfig way
+			PYTHON_SITE_PKG=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+				print (sysconfig.get_python_lib(0,0));"`
+		fi
 	fi
 	AC_MSG_RESULT([$PYTHON_SITE_PKG])
 	AC_SUBST([PYTHON_SITE_PKG])
 
+	#
+	# Check for platform-specific site packages
+	#
+	AC_MSG_CHECKING([for Python platform specific site-packages path])
+	if test -z "$PYTHON_PLATFORM_SITE_PKG"; then
+		if test "$IMPORT_SYSCONFIG" = "import sysconfig"; then
+			PYTHON_PLATFORM_SITE_PKG=`$PYTHON -c "
+$IMPORT_SYSCONFIG;
+if hasattr(sysconfig, 'get_default_scheme'):
+    scheme = sysconfig.get_default_scheme()
+else:
+    scheme = sysconfig._get_default_scheme()
+if scheme == 'posix_local':
+    # Debian's default scheme installs to /usr/local/ but we want to find headers in /usr/
+    scheme = 'posix_prefix'
+prefix = '$prefix'
+if prefix == 'NONE':
+    prefix = '$ac_default_prefix'
+sitedir = sysconfig.get_path('platlib', scheme, vars={'platbase': prefix})
+print(sitedir)"`
+		else
+			# distutils.sysconfig way
+			PYTHON_PLATFORM_SITE_PKG=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+				print (sysconfig.get_python_lib(1,0));"`
+		fi
+	fi
+	AC_MSG_RESULT([$PYTHON_PLATFORM_SITE_PKG])
+	AC_SUBST([PYTHON_PLATFORM_SITE_PKG])
+
 	#
 	# libraries which must be linked in when embedding
 	#
 	AC_MSG_CHECKING(python extra libraries)
 	if test -z "$PYTHON_EXTRA_LIBS"; then
-	   PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
-                conf = distutils.sysconfig.get_config_var; \
+	   PYTHON_EXTRA_LIBS=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+                conf = sysconfig.get_config_var; \
                 print (conf('LIBS') + ' ' + conf('SYSLIBS'))"`
 	fi
 	AC_MSG_RESULT([$PYTHON_EXTRA_LIBS])
@@ -275,8 +364,8 @@ EOD`
 	#
 	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; \
+		PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "$IMPORT_SYSCONFIG; \
+			conf = sysconfig.get_config_var; \
 			print (conf('LINKFORSHARED'))"`
 	fi
 	AC_MSG_RESULT([$PYTHON_EXTRA_LDFLAGS])
@@ -290,7 +379,7 @@ EOD`
 	ac_save_LIBS="$LIBS"
 	ac_save_LDFLAGS="$LDFLAGS"
 	ac_save_CPPFLAGS="$CPPFLAGS"
-	LIBS="$ac_save_LIBS $PYTHON_LIBS $PYTHON_EXTRA_LIBS $PYTHON_EXTRA_LIBS"
+	LIBS="$ac_save_LIBS $PYTHON_LIBS $PYTHON_EXTRA_LIBS"
 	LDFLAGS="$ac_save_LDFLAGS $PYTHON_EXTRA_LDFLAGS"
 	CPPFLAGS="$ac_save_CPPFLAGS $PYTHON_CPPFLAGS"
 	AC_LANG_PUSH([C])
@@ -306,7 +395,7 @@ EOD`
 
 	AC_MSG_RESULT([$pythonexists])
 
-        if test ! "x$pythonexists" = "xyes"; then
+	if test ! "x$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,