Use any available python version in configure cmake wrapper

configure.sh

@@ -0,0 +1,137 @@
+#!/bin/sh
+#
+# Copyright (C) 2004-2016 ZNC, see the NOTICE file for details.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# http://stackoverflow.com/questions/18993438/shebang-env-preferred-python-version
+# http://stackoverflow.com/questions/12070516/conditional-shebang-line-for-different-versions-of-python
+""":"
+which python3 >/dev/null 2>&1 && exec python3 "$0" "$@"
+which python  >/dev/null 2>&1 && exec python  "$0" "$@"
+which python2 >/dev/null 2>&1 && exec python2 "$0" "$@"
+echo "Error: configure wrapper requires python"
+exec echo "Either install python, or use cmake directly"
+":"""
+
+import argparse
+import os
+import subprocess
+import sys
+import re
+
+extra_args = [os.path.dirname(sys.argv[0])]
+parser = argparse.ArgumentParser()
+
+def gnu_install_dir(name, cmake=None):
+    if cmake is None:
+        cmake = name.upper()
+    parser.add_argument('--' + name, action='append', metavar=cmake,
+            dest='cm_args',
+            type=lambda s: '-DCMAKE_INSTALL_{}={}'.format(cmake, s))
+
+gnu_install_dir('prefix')
+gnu_install_dir('bindir')
+gnu_install_dir('sbindir')
+gnu_install_dir('libexecdir')
+gnu_install_dir('sysconfdir')
+gnu_install_dir('sharedstatedir')
+gnu_install_dir('localstatedir')
+gnu_install_dir('libdir')
+gnu_install_dir('includedir')
+gnu_install_dir('oldincludedir')
+gnu_install_dir('datarootdir')
+gnu_install_dir('datadir')
+gnu_install_dir('infodir')
+gnu_install_dir('localedir')
+gnu_install_dir('mandir')
+gnu_install_dir('docdir')
+
+
+group = parser.add_mutually_exclusive_group()
+group.add_argument('--enable-debug', action='store_const', dest='build_type',
+        const='Debug', default='Release')
+group.add_argument('--disable-debug', action='store_const', dest='build_type',
+        const='Release', default='Release')
+
+def tristate(name, cmake=None):
+    if cmake is None:
+        cmake = name.upper()
+    group = parser.add_mutually_exclusive_group()
+    group.add_argument('--enable-' + name, action='append_const',
+            dest='cm_args', const='-DWANT_{}=YES'.format(cmake))
+    group.add_argument('--disable-' + name, action='append_const',
+            dest='cm_args', const='-DWANT_{}=NO'.format(cmake))
+
+tristate('ipv6')
+tristate('openssl')
+tristate('zlib')
+tristate('perl')
+tristate('swig')
+tristate('cyrus')
+tristate('charset', 'ICU')
+tristate('tcl')
+
+class HandlePython(argparse.Action):
+    def __call__(self, parser, namespace, values, option_string=None):
+        extra_args.append('-DWANT_PYTHON=YES')
+        if values is not None:
+            x = re.search(r'\d.*', values)
+            if x:
+                extra_args.append('-DWANT_PYTHON_VERSION=' + x.group(0))
+
+group = parser.add_mutually_exclusive_group()
+group.add_argument('--enable-python', action=HandlePython, nargs='?',
+        metavar='PYTHON_VERSION')
+group.add_argument('--disable-python', action='append_const', dest='cm_args',
+        const='-DWANT_PYTHON=NO')
+
+parser.add_argument('--with-gtest', action='store', dest='gtest')
+parser.add_argument('--with-gmock', action='store', dest='gmock')
+
+class HandleSystemd(argparse.Action):
+    def __call__(self, parser, namespace, values, option_string=None):
+        extra_args.append('-DWANT_SYSTEMD=YES')
+        if values is not None:
+            extra_args.append('-DWANT_SYSTEMD_DIR=' + values)
+
+parser.add_argument('--with-systemdsystemunitdir', action=HandleSystemd,
+        nargs='?', metavar='UNITDIR')
+
+def env_type(s):
+    name, value = s.split('=', 1)
+    return (name, value)
+
+parser.add_argument('env', nargs='*', type=env_type, metavar='ENV_VAR=VALUE')
+
+args = parser.parse_args()
+
+cm_args = args.cm_args or []
+
+for env_key, env_value in args.env:
+    os.environ[env_key] = env_value
+if args.gtest:
+    os.environ['GTEST_ROOT'] = args.gtest
+if args.gmock:
+    os.environ['GMOCK_ROOT'] = args.gmock
+
+if os.environ.get('CXX') is not None:
+    extra_args.append('-DCMAKE_CXX_COMPILER=' + os.environ['CXX'])
+
+try:
+    os.remove('CMakeCache.txt')
+except OSError:
+    pass
+subprocess.check_call(['cmake', '-DCMAKE_BUILD_TYPE=' + args.build_type]
+        + cm_args + extra_args)