add: show more command-line arguments to control which
python is used and where py/pyext files should be installed.
The new options are in addition to the existing PYTHON, PYTHONDIR,
and PYTHONARCHDIR environment variable, providing the help messages
to the user, so it can easily change parameters without second-guessing
of what are they.
Environmental parameters override command line arguments (is it right?)
updated: An extension to Configure.find_command to allow specification
of the name for the searched command (using `msg` option). This is
helpful when the search command is a huge list, as in the case of
python's python-config case.
updated: Do not specify prefix for `get_python_lib`, since this way it
can result in a wrong PYTHONDIR and PYTHONARCHDIR on certain platforms
(e.g., OSX)
updated: Changing logic with byte-compilation of python files. Mow, files are
compiled during the build stage, not install stage. During the
install stage files are simply copied to the requested
location.
updated: If there is an error in python source code, byte-compilation
phase will raise an exception and abort building process.
Signed-off-by: Thomas Nagy <tnagy2pow10@gmail.com>