cleaning up XPath error reporting that time. applied the two patches for

* error.c include/libxml/xmlerror.h include/libxml/xpath.h
  include/libxml/xpathInternals.h xpath.c: cleaning up XPath
  error reporting that time.
* threads.c: applied the two patches for TLS threads
  on Windows from Jesse Pelton
* parser.c: tiny safety patch for xmlStrPrintf() make sure the
  return is always zero terminated. Should also help detecting
  passing wrong buffer size easilly.
* result/VC/* result/valid/rss.xml.err result/valid/xlink.xml.err:
  updated the results to follow the errors string generated by
  last commit.
Daniel
diff --git a/result/VC/NS3 b/result/VC/NS3
index e798978..72c0117 100644
--- a/result/VC/NS3
+++ b/result/VC/NS3
@@ -1,9 +1,9 @@
-./test/VC/NS3:9: validity error : Value for attribute xmlns of foo is different from default "http://example.com/fooo"
+./test/VC/NS3:9: element foo: validity error : Value for attribute xmlns of foo is different from default "http://example.com/fooo"
 xmlns="http://example.com/foo" xmlns:foo="http://example.com/fo" foo:info="toto"
                                                                                ^
-./test/VC/NS3:9: validity error : Value for attribute xmlns of foo must be "http://example.com/fooo"
+./test/VC/NS3:9: element foo: validity error : Value for attribute xmlns of foo must be "http://example.com/fooo"
 xmlns="http://example.com/foo" xmlns:foo="http://example.com/fo" foo:info="toto"
                                                                                ^
-./test/VC/NS3:9: validity error : Element foo namespace name for default namespace does not match the DTD
+./test/VC/NS3:9: element foo: validity error : Element foo namespace name for default namespace does not match the DTD
 mlns="http://example.com/foo" xmlns:foo="http://example.com/fo" foo:info="toto"/
                                                                                ^