Re: HTML format documentation

[Richard Stallman]

    Anyway, making this option an install-time option is probably not a
    good idea.  Many programs will want to know, at compile-time, where
    the configuration files are going to be installed.  If they just take
    sysconfdir from build time, they'd look for them in /usr/etc, instead
    of /etc, where they were installed.

Indeed, the option must be meaningful at build time, since that is
where prefix and sysconfdir are used.

But this does not necessarily mean it ought to be a configure-time
option.  It could be a build-time option like prefix and sysconfdir.