bug#47800: [native-comp] could not resolve realpath of "emacs"

[Eli Zaretskii]

> From: wilde@sha-bang.de
> Date: Fri, 16 Apr 2021 11:53:58 +0200
> 
> FWIW: when /proc/self/exe exists it is a symlink to the currently
> running executable, that should make the implementation of
> find_executable() in these cases straight forward.
> 
> Basically:
>   realpath ("/proc/self/exe", NULL);
> should do the job.

This was discussed, but AFAIR people felt uneasy with using it.