This sets the SGML_CATALOG_FILES, similar to how libxml2 does the same with XML_CATALOG_FILES. I based the hook on the libxml2 one, and I followed the instructions about this variable here: http://docbook.sourceforge.net/release/dsssl/1.79/doc/install.html
(I may have broken openjade... I will check later). svn path=/nixpkgs/trunk/; revision=19697
svn path=/nixpkgs/trunk/; revision=17926