bug#20968: 25.0.50; Be able to specify the output directory for `byte-compile-file'

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 4 Jul 2015 11:20:05 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: rgm@gnu.org, 20968@debbugs.gnu.org
> 
> > > But AFAIK, the behavior is well-defined.
> > 
> > It's well-defined only for the current behavior, where the *.el and
> > the corresponding *.elc files live in the same directory.
> 
> How so?  Please give a concrete example where it is not well-defined
> for a foo.el and a foo.elc that are in different directories.  Explain
> what problems you think arise in such a case.

I already did that: we search load-path linearly, only once, looking
for .el and .elc files in each directory.

> Can you please point out just what the problems are?

Sorry, don't have all that time.  You will have to read the code to
understand what I'm talking about.  The function 'openp' in lread.c is
the starting point, and the next step is to read the implementation of
'load'.