The only file that actually referred to the Python interpreter was
share/boost-build/example/customization/inline_file.py. So get rid of
the whole example directory.
Install names need to be absolute paths, otherwise programs that link
against the dylib won't work without setting $DYLD_LIBRARY_PATH. Most
packages do this correctly, but some (like Boost and ICU) do not.
This setup hook absolutizes all install names.
