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

[Glenn Morris]

Glenn Morris wrote:

> Stefan Monnier wrote:
>
>> The case I know of where the .elc and .el are not next to each other is
>> to place the byte-compiled files in a directory specific to the Emacs
>> version used to compile.  This is used in Debian so as to be able to
>> have Elisp packages and byte-compiled for many different
>> (X)Emacs versions.
>
> I had a vague memory that this caused Some Issues, but I don't remember
> any details.

The obvious one is whether .el is newer than .elc.
I also thought it was something to do with the documentation lookup.

In fact on my Debian system, looks like they use symlinks to link the
source .el into the directory with the version-specific .elc. Probably
to avoid those very problems that come from separating the .el and .elc.

But hey, patches welcome if someone wants to address this long-standed,
complicated issue.