Better way to do conditional inclusion in make

[Simon J. Gerraty]

Julian Elischer <julian at freebsd.org> wrote:
> how does it cope with the case where a single file is dependent on
> either of two options.
> (we have this in our tree.. not sure if it occurs in the FreeBSD tree.)
> file could occur in both lists or twice in one list..

If you accept the premise that order of the list shouldn't matter,
one can simply apply :O:u to suppress dups.