[pca] Can pca check two different local sources?

[Craig S. Bell]

  Martin, regarding pca-dev and multi-element xrefurl: Should "pca -x"
always try the proxy when I include proxy-specific options such as
"-F" and/or "--nocache"?

  My client xrefurl lists file:/ first, then the proxy URL.  The proxy
uses that same file:/ path for patchdir and xrefdir.  I imagine that
"-F" also affects README files via patchurl.

  When I use these options, pca-dev gets the file:/ edition, without
checking age.  I assumed that it would try the proxy first (if
pca-proxy.cgi is found anywhere in xrefurl).

  Easy workaround: Just specify "--xrefurl=http://proxy/pca-proxy.cgi"
on the command-line.  The trick is writing one clever xrefurl that
handles the most use cases.  =-)

  When I'm not using "-F" or "--nocache", I still want the ability to
use an arbitrary xref file without checking the timestamp, i.e. a
"golden" xref that I have set aside.

  These are my own assumptions, so let me know if I'm thinking about
this incorrectly.  How do you intend for this to behave?  Thanks as
always... -cheers, CSB