Similarly, the variable sys.exec_prefix gives the site-specific directory prefix where the platform dependent Python files are installed; by default, this is also "/usr/local". This can be set at build time with the –exec-prefix argument to the configure script. Specifically, all configuration files (e.g. the config.h header file) are installed in the directory sys.exec_prefix+"/lib/python1.4/config", and shared library modules are installed in sys.exec_prefix+"/lib/python1.4/sharedmodules".
Include files are at sys.prefix+"/include/python1.4".
It is not yet decided what the most portable way is to come up with the version number used in these pathnames. For compatibility with the 1.4beta releases, sys.version[:3] can be used.
On non-Unix systems, these variables are meaningless.
After this path manipulation has been performed, an attempt is made to import the module sitecustomize. Any ImportError exception raised by this attempt is silently ignored.