bin/117831: csup is incompatible WRT handling unknown RCS keywords

[YONETANI Tomokazu]

On Mon, Nov 05, 2007 at 05:47:25PM +0000, remko at FreeBSD.org wrote:
> Over to maintainer.
> http://www.freebsd.org/cgi/query-pr.cgi?pr=117831

Ok, obviously I overlooked at what's written in TODO file:

  BUGS:
		:
  - Add missing support for supfile keywords and add sanity checks for
    some of them.  Also, we're not supposed to choke on unknown keywords
    to stay in line with CVSup, which just ignores them in order to
    maintain compatibility with sup configuration files.

so the author had already identified this problem far before I poked at him.

IMHO, ignoring an unknown keyword(a newphrase) is just OK, as long as it
spews a warning.  As many existing RCS/CVS tools are designed to behave
this way anyway, one won't (can't) add a newphrase which requires older
applications to upgrade and support it to operate on the new repository
properly.