bug#46790: 28.0.50; make install with native-comp branch

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 24 Apr 2021 10:49:07 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: psainty@orcon.net.nz, 46790@debbugs.gnu.org
> 
>   . where is the _real_ Emacs executable?
>   . where is the symlink to it?
>   . are you invoking the symlink explicitly or via PATH?
>   . where is the .pdmp file?
>   . where is the installed native-lisp/ directory?

Also I've now tried to improve the diagnostics when Emacs fails to
find the *.eln files, so please report what it says when it fails.

In addition: you said earlier:

> Emacs IS starting though but is not finding needed libraries.

Maybe I misunderstand the problem.  Your original report quoted error
messages like these:

> thierry <at> IPadS340:/usr/local/sbin/emacs-28.0.50$ ./emacs-28.0.50
> emacs: /usr/local/sbin/emacs-28.0.50/../native-lisp/28.0.50-40158ec0/window-0d1b8b93-738411b0.eln: cannot open shared object file: No such file or directory
> thierry <at> IPadS340:/usr/local/sbin/emacs-28.0.50$ ./emacs
> emacs: /usr/local/sbin/emacs-28.0.50/../native-lisp/28.0.50-40158ec0/window-0d1b8b93-738411b0.eln: cannot open shared object file: No such file or directory

AFAIK these are fatal errors: Emacs doesn't start up when it reports
these.  But you seem to be saying Emacs does start in your case?  Then
what do you mean by "is not finding needed libraries"?