out: proxyable=, in: once-per= and proxy-hosts=

OK, I've checked into CVS all the changes (including
documentation) for the proxy-host stuff mentioned in the
previous message.  Or, more accurately, it's the same old
stuff in the new form: I haven't implemented anything new
(yet).

It passes the sample1:try-ark test.  Still, unless you can
stomach the prospect of reading ARK's inner Python code, you
might steer clear for a few days.

The changes to .xml files are pretty automatic:

1. proxyable="."
   to
   once-per="site"

2. proxyable="_HOSTS_SUPPORTED_"
   to
   once-per="hosts-supported"

3. a little tags-query-replace for the @host:...@ to
   @proxy-host:...@ changes:

   (tags-query-replace "@host:\\(SED\\|SU\\|SBIN_SH\\|GNU_FIND\\|GNU_XARGS\\|CAT\\|GROFF\\|GNU-XGETTEXT\\|GNU_M4\\|GZIP\\|GNU-TAR\\|HOSTNAME\\|CMP\\|DIRNAME\\|BASENAME\\|GNU_M4_P\\|PS_E\\|INETD\\|UNZIP\\|PERL\\|PYTHON\\|MKDIR_P\\|TAR\\|LNDIR\\|MAKE\\|CC\\|CXX\\|CFLAGS\\|CPPFLAGS\\|CXXFLAGS\\|LDFLAGS\\|PATCH\\|GNU_TAR\\|SUDO\\|GNU_MAKE\\|EGREP\\|TOUCH\\|FIND\\|XARGS\\|MD5SUM\\|GNU_DIFF\\|GNU_FINDUTILS\\|HEAD\\|KILL\\|CVS\\|CHMOD\\|CHGRP\\|CHOWN\\|LN\\|CONFIG-GUESS\\|BSD_INSTALL\\)@" "@proxy-host:\\1@" nil)

4. The same again, but with _BOOT on the end of those.

(If you don't know how to do tags-query-replace across a few
hundred files [in Emacs, or some other way], go learn now.
It's incredibly useful.)

Will