MFC r249591:
    Document jail_<jname>_parameters option.

    The description explains why we should not configure "path",
    "host.hostname", "command", "ip4.addr" and ip6.addr" parameters with
    this, but rather use the historical rc.conf(5) options.
MFC r250992:
    Rework the comment I initially wrote when SHLIB_LDSCRIPT was introduced.
    The build system is really intricate and I had a hard time to remind the
    whole picture even when reading my own words.  This one will hopefully
    be better.