docbook xsl: use a more correct layout

Borrowed from Linux From Scratch.

app-text/docbook_xsl_stylesheets/docbook_xsl_stylesheets-1.78.1.recipe

@@ -35,6 +35,12 @@ BUILD()
 
 INSTALL()
 {
-	mkdir -p $dataDir/xml
-	find . -maxdepth 1 -type f -exec cp -r {} $dataDir/xml/ \;
+	mkdir -p $dataDir/xml/docbook/xsl-stylesheets-1.78.1
+
+	cp -v -R VERSION common eclipse epub extensions fo highlighting html \
+		htmlhelp images javahelp lib manpages params profiling \
+		roundtrip slides template tests tools webhelp website \
+		xhtml xhtml-1_1 $dataDir/xml/docbook/xsl-stylesheets-1.78.1
+
+	ln -s VERSION $dataDir/xml/docbook/xsl-stylesheets-1.78.1/VERSION.xsl
 }