This is the simplification I mentioned before for the way
checkdoc-proper-noun-regexp is built.

You'd be tempted to build the regexp within
checkdoc-proper-noun-region-engine (maybe just with mapconcat) for
easier customizing of checkdoc-proper-noun-list, but I suppose nobody
changes it.

2009-11-13  Kevin Ryde  <user42@zip.com.au>

	* emacs-lisp/checkdoc.el (checkdoc-proper-noun-regexp): Build
	value with regexp-opt instead of explicit joining loop.