some cleanup checking for xmllint and xsltproc in configure.in, fixed make

* configure.in doc/Makefile.am xstc/Makefile.am: some cleanup
  checking for xmllint and xsltproc in configure.in, fixed
  make dist w.r.t. the new xstc subdir.
* doc/*: rebuilt
Daniel
diff --git a/doc/APIchunk25.html b/doc/APIchunk25.html
index d734f7c..f19743f 100644
--- a/doc/APIchunk25.html
+++ b/doc/APIchunk25.html
@@ -168,6 +168,7 @@
 </dd><dt>with_ns</dt><dd><a href="html/libxml-xpath.html#_xmlNodeSet">_xmlNodeSet</a><br />
 </dd><dt>within</dt><dd><a href="html/libxml-valid.html#_xmlValidCtxt">_xmlValidCtxt</a><br />
 <a href="html/libxml-xmlautomata.html#xmlAutomataNewCounterTrans">xmlAutomataNewCounterTrans</a><br />
+<a href="html/libxml-xmlstring.html#xmlGetUTF8Char">xmlGetUTF8Char</a><br />
 <a href="html/libxml-tree.html#xmlNewDocComment">xmlNewDocComment</a><br />
 <a href="html/libxml-tree.html#xmlNewDocNode">xmlNewDocNode</a><br />
 <a href="html/libxml-tree.html#xmlNewDocNodeEatName">xmlNewDocNodeEatName</a><br />