Allow overriding the Python version.
The Python setuptools based build system already modifies shebangs.
The Python scripts have unversioned Python shebangs so they
will fail if an unversioned Python is not provided by the OS.
The Debian bullseye release will not have an unversioned Python by default.
Avoid make pattern rules and shell functions since they are not portable.
BSD install doesn't understand the -D option. Use a separate install
command to create the directory (with the -d option) before installing
the file.
Signed-off-by: Brian Gernhardt <brian@gernhardtsoftware.com>
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
