and sent in by Greg Hudson as seen in PR misc/3227. Basically what it
does is adds a flushall option which deletes all but localhost routes.
This is done by andoring in a flag called doall (1 means do all routes
including gateway, 0 means do a regular flush). I have seen some
platforms that do this. I tested it out on ipv4 only, it works as
advertised. Commit was approved by christos@.
Also allow compilation with -DSMALL to ommit support for
non-essential protocols (i.e. when built into a ramdisk).
Use a less hack-ish way to generate keywords.[ch] and just
check in the result (helps ../../distrib/utils/x_route).
