fixed compilation when configured --without-sax1 and other cleanups fixes

* SAX2.c globals.c runtest.c testC14N.c testapi.c tree.c
  include/libxml/SAX2.h include/libxml/xmlregexp.h: fixed compilation
  when configured --without-sax1 and other cleanups fixes bug #172683
* doc/* elfgcchack.h: regenerated
Daniel
diff --git a/elfgcchack.h b/elfgcchack.h
index 3af65aa..ca69dbf 100644
--- a/elfgcchack.h
+++ b/elfgcchack.h
@@ -8591,7 +8591,7 @@
 #endif
 #endif
 
-#if defined(LIBXML_SAX1_ENABLED) || defined(LIBXML_HTML_ENABLED)
+#if defined(LIBXML_SAX1_ENABLED) || defined(LIBXML_HTML_ENABLED) || defined(LIBXML_WRITER_ENABLED) || defined(LIBXML_DOCB_ENABLED)
 #ifdef bottom_SAX2
 #undef xmlSAX2EndElement
 extern __typeof (xmlSAX2EndElement) xmlSAX2EndElement __attribute((alias("xmlSAX2EndElement__internal_alias")));
@@ -8837,7 +8837,7 @@
 #endif
 #endif
 
-#if defined(LIBXML_SAX1_ENABLED) || defined(LIBXML_HTML_ENABLED)
+#if defined(LIBXML_SAX1_ENABLED) || defined(LIBXML_HTML_ENABLED) || defined(LIBXML_WRITER_ENABLED) || defined(LIBXML_DOCB_ENABLED)
 #ifdef bottom_SAX2
 #undef xmlSAX2StartElement
 extern __typeof (xmlSAX2StartElement) xmlSAX2StartElement __attribute((alias("xmlSAX2StartElement__internal_alias")));