added overlay support

Author: moonbuggy

.autoconf/ax_python.m4

@@ -0,0 +1,97 @@
+# ===========================================================================
+#        https://www.gnu.org/software/autoconf-archive/ax_python.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PYTHON
+#
+# DESCRIPTION
+#
+#   This macro does a complete Python development environment check.
+#
+#   It checks for all known versions. When it finds an executable, it looks
+#   to find the header files and library.
+#
+#   It sets PYTHON_BIN to the name of the python executable,
+#   PYTHON_INCLUDE_DIR to the directory holding the header files, and
+#   PYTHON_LIB to the name of the Python library.
+#
+#   This macro calls AC_SUBST on PYTHON_BIN (via AC_CHECK_PROG),
+#   PYTHON_INCLUDE_DIR and PYTHON_LIB.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Michael Tindal
+#
+#   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, see <https://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
+
+AC_DEFUN([AX_PYTHON],
+[AC_MSG_CHECKING(for python build information)
+AC_MSG_RESULT([])
+for python in python3.7 python3.6 python3.5 python3.4 python3.3 python3.2 python3.1 python3.0 python2.7 python2.6 python2.5 python2.4 python2.3 python2.2 python2.1 python; do
+AC_CHECK_PROGS(PYTHON_BIN, [$python])
+ax_python_bin=$PYTHON_BIN
+if test x$ax_python_bin != x; then
+   AC_CHECK_LIB($ax_python_bin, main, ax_python_lib=$ax_python_bin, ax_python_lib=no)
+   if test x$ax_python_lib == xno; then
+     AC_CHECK_LIB(${ax_python_bin}m, main, ax_python_lib=${ax_python_bin}m, ax_python_lib=no)
+   fi
+   if test x$ax_python_lib != xno; then
+     ax_python_header=`$ax_python_bin -c "from distutils.sysconfig import *; print(get_config_var('CONFINCLUDEPY'))"`
+     if test x$ax_python_header != x; then
+       break;
+     fi
+   fi
+fi
+done
+if test x$ax_python_bin = x; then
+   ax_python_bin=no
+fi
+if test x$ax_python_header = x; then
+   ax_python_header=no
+fi
+if test x$ax_python_lib = x; then
+   ax_python_lib=no
+fi
+
+AC_MSG_RESULT([  results of the Python check:])
+AC_MSG_RESULT([    Binary:      $ax_python_bin])
+AC_MSG_RESULT([    Library:     $ax_python_lib])
+AC_MSG_RESULT([    Include Dir: $ax_python_header])
+
+if test x$ax_python_header != xno; then
+  PYTHON_INCLUDE_DIR=$ax_python_header
+  AC_SUBST(PYTHON_INCLUDE_DIR)
+fi
+if test x$ax_python_lib != xno; then
+  PYTHON_LIB=$ax_python_lib
+  AC_SUBST(PYTHON_LIB)
+fi
+])dnl

.autoconf/ax_require_defined.m4

@@ -0,0 +1,38 @@
+# ===========================================================================
+#    https://www.gnu.org/software/autoconf-archive/ax_require_defined.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_REQUIRE_DEFINED(MACRO)
+#
+# DESCRIPTION
+#
+#   AX_REQUIRE_DEFINED is a simple helper for making sure other macros have
+#   been defined and thus are available for use.  This avoids random issues
+#   where a macro isn't expanded.  Instead the configure script emits a
+#   non-fatal:
+#
+#     ./configure: line 1673: AX_CFLAGS_WARN_ALL: command not found
+#
+#   It's like AC_REQUIRE except it doesn't expand the required macro.
+#
+#   Here's an example:
+#
+#     AX_REQUIRE_DEFINED([AX_CHECK_LINK_FLAG])
+#
+# LICENSE
+#
+#   Copyright (c) 2014 Mike Frysinger <vapier@gentoo.org>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 2
+
+AC_DEFUN([AX_REQUIRE_DEFINED], [dnl
+  m4_ifndef([$1], [m4_fatal([macro ]$1[ is not defined; is a m4 file missing?])])
+])dnl AX_REQUIRE_DEFINED
+