trivial-features ensures consistent *FEATURES* across multiple
Common Lisp implementations.

For example, on MacOS X platforms, while most Lisps push :DARWIN
to *FEATURES*, CLISP and Allegro push :MACOS and :MACOSX instead,
respectively. Some Lisps might not push any feature suggesting MacOS
X at all. trivial-features will make sure all Lisps will have :DARWIN
in the *FEATURES* list when running on MacOS X.

WWW: http://www.cliki.net/trivial-features