Fixed performance bug in UIOP:DIRECTORY-FILES

[Robert Goldman]

On 6/10/16 Jun 10 -8:41 PM, Faré wrote:
> I bumped ASDF to 3.1.7.1 after I fixed a performance bug in
> directory-files that made it quadratic instead of linear, due to some
> remove-duplicates used for logical-pathnames.
> The fix was to only use this quadratic behavior for LPNs. If you use
> LPNs, you deserve to lose on large directories. LPNs are for legacy
> Lisp code with relatively few files, only.
> 
> —♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
> The best of all regimes is one where I am the head honcho of a worldwide empire.
>  — Winston Churchill (his most famous quip, as translated to plain English)
> 

On the Mac, this fails testing on clisp: looks like a regression.  See
launchpad ticket: https://bugs.launchpad.net/asdf/+bug/1592180

Looks like maybe there was always a bug here on clisp, but when you took
out the REMOVE-DUPLICATES, you revealed it.

Please have a look at this, thanks!
r