cleanup cleanup too added xmlNoNetExternalEntityLoader() from xsltproc

* Makefile.am: cleanup
* threads.c: cleanup too
* xmlIO.c include/libxml/xmlIO.h: added xmlNoNetExternalEntityLoader()
  from xsltproc
* include/libxml/tree.h include/libxml/parser.h: trying to break a
  dependancy loop.
Daniel
diff --git a/Makefile.am b/Makefile.am
index 98aea6e..dd4d960 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -443,7 +443,7 @@
 	@echo "##"
 	@echo "## Threaded regression tests"
 	@echo "##"
-	testThreads
+	$(top_builddir)/testThreads
 
 SAXtests : testSAX
 	@(echo > .memdump)