Fix #49: add support for -8 command line option to allow 8-bit data

This patch allows the user to disable the 8-bit data check in the log
message validator.  If you have experienced problems with logging any
unicode (utf-8) messages after v1.6, this option is for you.

The correct way to handle this is to add proper parser support for the
Unicode BOM, defined in RFC5424[1], as NetBSD syslogd does[2], search
for IS_BOM().

[1]: https://datatracker.ietf.org/doc/html/rfc5424#appendix-A.8
[2]: http://cvsweb.netbsd.org/bsdweb.cgi/src/usr.sbin/syslogd/syslogd.c?rev=1.138

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

man/syslogd.8

@@ -38,7 +38,7 @@
 .Nd log systems messages
 .Sh SYNOPSIS
 .Nm
-.Op Fl ?46AdFHKknsTtv
+.Op Fl ?468AdFHKknsTtv
 .Op Fl a Ar addr[/len][:port]
 .Op Fl a Ar name[:port]
 .Op Fl b Ar addr[:port]
@@ -129,6 +129,22 @@ to use IPv4 addresses only.
 Force
 .Nm
 to use IPv6 addresses only.
+.It Fl 8
+Tells
+.Nm
+not to interfere with 8-bit data.  Normally
+.Nm
+replaces C1 control characters
+.Pq ISO 8859 and Unicode characters
+with their
+.Dq M- Ns Em x
+equivalent.  Note, this option does not change the way
+.Nm
+alters control characters
+.Pq see Xr iscntrl 3 .
+They are always replaced with their
+.Dq ^ Ns Em x
+equivalent.
 .It Fl A
 Ordinarily,
 .Nm