Changes

This means that the script will look for Python in the PATH environmental variable (in Linux, Mac OS X, and MS Windows) and use that one rather than the Python version it was installed for. This is a fatal problem when multiple Python versions are present as the SCons files are installed as a site-package only for the specific Python version. There are two methods to overcome this difficulty, either by modifying the SCons source file or by pointing to the correct Python and SCons versions.