Some environment variables can be set before running ./configure to tune the installation process. This can be used to specify the locations of components which are installed but can't be found by ./configure in "standard" locations. For example, you could pass the location of the DocBook DTD by running ./configure as:
$  DBK_XML_DTD=/home/flacoste/xml/docbook-xml-4.1.2/docbookx.dtd \
 ./configure
	  
The following list explains the purpose of each variable.
PERLSets the path to the perl interpreter.
JADESets the path to the jade DSSSL interpreter. This is only needed when you build from CVS.
PDFJADETEXSets the path to the pdfjatetex command. This is only needed when you build from CVS.
XSLTPROCSets the path to the xsltproc XSLT processor. This is only needed when you build from CVS.
DBK_XML_DTDSets the path to the DocBook XML Document Type Declaration. This should point to the XML V4.1.2 DTD. This is only needed when you build from CVS.
DBK_XSL_STYLESHEETSSets the path to the directory which contains
	      Norman Walsh's XSL stylesheets for DocBook. (This
	      directory should contain subdirectories named
	      fo, html or
	      xhtml.) This is only needed when
	      you build from CVS.
	      
DBK_DSSSL_STYLESHEETSSets the path to the directory which contains
	      Norman Walsh's DSSSL stylesheets for DocBook. (This
	      directory should contain a subdirectory named
	      print.) This is only needed when
	      you build from CVS.