Fix ./configure handling of OS_* for GNU/kFreeBSD.

Thanks to Robert Edmonds <edmonds@debian.org> for the initial report.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Update bup-split(1); document -d, clarify the split "modes", and reorganize.

Update the synopsis, document the "-d DATE" option, and make a clearer
distinction between normal options and the options that select the
split "mode".

Signed-off-by: Gabriel Filion <gabster@lelutin.ca>
[rlb@defaultvalue.org: add dashes to seconds-since-epoch; adjust the
 MODES text a bit and move -b down; make a few other edits and adjust
 commit message.]
Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Update bup split -h output (optspec) to distinguish between split "modes".

Split it into three lines to clearly show that some modes don't fare
well with others.

Signed-off-by: Gabriel Filion <gabster@lelutin.ca>
[rlb@defaultvalue.org: adjust commit message.]
Reviewed-by: Rob Browning <rlb@defaultvalue.org>
Mention --git-ids in bup split -h output sample commands.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
write_idx: make filename char* non-const (fixes python 2.6.6 compatibility).

Thanks to Alexander Barton <alex@barton.de> for the report.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Quash stat(2) st_rdev unless we're going to need it for mknod().

On some platforms (i.e. kFreeBSD), the st_rdev value isn't completely
stable.  For example, given "date > foo; cp -a foo foo-2", the st_rdev
value may differ between the two files.

Since we only need the st_rdev value for the call to mknod() when
restoring character and block special files, set it to zero for
anything else.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Ignore unimplemented metadata record during read (_rec_tag_nfsv4_acl).

Don't test for _rec_tag_nfsv4_acl and then try to call an
unimplemented method in Metadata.read().  Otherwise, if/when we do add
support, older versions of bup will choke on it.

Thanks to Alexander Barton <alex@barton.de> for pointing this out.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>