updated the docs and rebuild releasing 2.6.21 removed

* NEWS elfgcchack.h testapi.c doc/*: updated the docs and rebuild
  releasing 2.6.21
* include/libxml/threads.h threads.c: removed xmlIsThreadsEnabled()
* threads.c include/libxml/threads.h xmllint.c: added the more
  generic xmlHasFeature() as suggested by Bjorn Reese, xmllint uses it.
Daniel
diff --git a/doc/APIsymbols.html b/doc/APIsymbols.html
index fe26d0d..d0fe11d 100644
--- a/doc/APIsymbols.html
+++ b/doc/APIsymbols.html
@@ -413,6 +413,37 @@
 <a href="html/libxml-entities.html#XML_EXTERNAL_GENERAL_PARSED_ENTITY">XML_EXTERNAL_GENERAL_PARSED_ENTITY</a><br />
 <a href="html/libxml-entities.html#XML_EXTERNAL_GENERAL_UNPARSED_ENTITY">XML_EXTERNAL_GENERAL_UNPARSED_ENTITY</a><br />
 <a href="html/libxml-entities.html#XML_EXTERNAL_PARAMETER_ENTITY">XML_EXTERNAL_PARAMETER_ENTITY</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_AUTOMATA">XML_FEATURE_AUTOMATA</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_C14N">XML_FEATURE_C14N</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_CATALOG">XML_FEATURE_CATALOG</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_DEBUG">XML_FEATURE_DEBUG</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_DEBUG_MEM">XML_FEATURE_DEBUG_MEM</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_DEBUG_RUN">XML_FEATURE_DEBUG_RUN</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_EXPR">XML_FEATURE_EXPR</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_FTP">XML_FEATURE_FTP</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_HTML">XML_FEATURE_HTML</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_HTTP">XML_FEATURE_HTTP</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_ICONV">XML_FEATURE_ICONV</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_ISO8859X">XML_FEATURE_ISO8859X</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_LEGACY">XML_FEATURE_LEGACY</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_MODULES">XML_FEATURE_MODULES</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_NONE">XML_FEATURE_NONE</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_OUTPUT">XML_FEATURE_OUTPUT</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_PATTERN">XML_FEATURE_PATTERN</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_PUSH">XML_FEATURE_PUSH</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_READER">XML_FEATURE_READER</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_REGEXP">XML_FEATURE_REGEXP</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_SAX1">XML_FEATURE_SAX1</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_SCHEMAS">XML_FEATURE_SCHEMAS</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_SCHEMATRON">XML_FEATURE_SCHEMATRON</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_THREAD">XML_FEATURE_THREAD</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_TREE">XML_FEATURE_TREE</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_UNICODE">XML_FEATURE_UNICODE</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_VALID">XML_FEATURE_VALID</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_WRITER">XML_FEATURE_WRITER</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_XINCLUDE">XML_FEATURE_XINCLUDE</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_XPATH">XML_FEATURE_XPATH</a><br />
+<a href="html/libxml-parser.html#XML_FEATURE_XPTR">XML_FEATURE_XPTR</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_C14N">XML_FROM_C14N</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_CATALOG">XML_FROM_CATALOG</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_CHECK">XML_FROM_CHECK</a><br />
@@ -1910,6 +1941,7 @@
 <a href="html/libxml-xmlregexp.html#xmlExpStringDerive">xmlExpStringDerive</a><br />
 <a href="html/libxml-xmlregexp.html#xmlExpSubsume">xmlExpSubsume</a><br />
 <a href="html/libxml-parser.html#xmlExternalEntityLoader">xmlExternalEntityLoader</a><br />
+<a href="html/libxml-parser.html#xmlFeature">xmlFeature</a><br />
 <a href="html/libxml-xmlIO.html#xmlFileClose">xmlFileClose</a><br />
 <a href="html/libxml-xmlIO.html#xmlFileMatch">xmlFileMatch</a><br />
 <a href="html/libxml-xmlIO.html#xmlFileOpen">xmlFileOpen</a><br />
@@ -1989,6 +2021,7 @@
 <a href="html/libxml-globals.html#xmlGlobalState">xmlGlobalState</a><br />
 <a href="html/libxml-globals.html#xmlGlobalStatePtr">xmlGlobalStatePtr</a><br />
 <a href="html/libxml-parserInternals.html#xmlHandleEntity">xmlHandleEntity</a><br />
+<a href="html/libxml-parser.html#xmlHasFeature">xmlHasFeature</a><br />
 <a href="html/libxml-tree.html#xmlHasNsProp">xmlHasNsProp</a><br />
 <a href="html/libxml-tree.html#xmlHasProp">xmlHasProp</a><br />
 <a href="html/libxml-hash.html#xmlHashAddEntry">xmlHashAddEntry</a><br />
@@ -2085,7 +2118,6 @@
 <a href="html/libxml-chvalid.html#xmlIsPubidChar_ch">xmlIsPubidChar_ch</a><br />
 <a href="html/libxml-chvalid.html#xmlIsPubidChar_tab">xmlIsPubidChar_tab</a><br />
 <a href="html/libxml-valid.html#xmlIsRef">xmlIsRef</a><br />
-<a href="html/libxml-threads.html#xmlIsThreadsEnabled">xmlIsThreadsEnabled</a><br />
 <a href="html/libxml-tree.html#xmlIsXHTML">xmlIsXHTML</a><br />
 <a href="html/libxml-parser.html#xmlKeepBlanksDefault">xmlKeepBlanksDefault</a><br />
 <a href="html/libxml-globals.html#xmlKeepBlanksDefaultValue">xmlKeepBlanksDefaultValue</a><br />