tar 1.13, -C and -T don't work together

[Greg Wooledge]

I'm using GNU tar 1.13 on HP-UX 10.20.  One of my users is writing a
backup script using GNU tar and wants to combine the -C and --files-from
switches, like this:

    .... | tar rvf $writeto -C /a/directory/name --files-from -

No matter what ordering or spelling we use for the -C/--directory and
-T/--files-from options, it seems that -C is completely ignored whenever
-T is used.  If I change the tar command to this:

    .... | (cd /a/directory/name; tar rvf $writeto --files-from -)

then it works as expected.