In -STABLE, this is default, in -CURRENT it is not, which leads to many a
headache for a user coming to -CURRENT without remembering this fact. It
is one of the POLA violations we have not avoided by preparing the users
for it appopriately. Therefore, a warnx(3) is added here, explicitly to
be MFC'd shortly to start the re-education process rolling.
Reviewed by: General murmurs of approval in that IRC channel.
MFC after: 3 days
ec6c14f6eb