Will Robertson wrote:

> 
> In the spirit of being hasty, (I think I can get away with it in this
> case) I've now added your code to the beginning of l3names and removed
> the \engine_if_etex conditional from l3basics.

Will,

You've added for initex as well as for the package.  For initex, you'd
need to have a different test (or change both), as I've used
\@ifundefined and \PackageError, which of course need LaTeX2e.
-- 
Joseph Wright