Good old cycle: new release, new bug reports, new fixes ...
- HTMLtree.c HTMLtree.h : closing #53402 i.e. output of
  PIs when using xsl:output
- valid.c: closing #53537 some case generate segfaults if there
  is validity errors
Daniel
diff --git a/include/libxml/HTMLtree.h b/include/libxml/HTMLtree.h
index 543d693..3888f7c 100644
--- a/include/libxml/HTMLtree.h
+++ b/include/libxml/HTMLtree.h
@@ -23,6 +23,7 @@
 #define HTML_ENTITY_REF_NODE	XML_ENTITY_REF_NODE
 #define HTML_COMMENT_NODE	XML_COMMENT_NODE
 #define HTML_PRESERVE_NODE	XML_CDATA_SECTION_NODE
+#define HTML_PI_NODE		XML_PI_NODE
 
 htmlDocPtr	htmlNewDoc		(const xmlChar *URI,
 					 const xmlChar *ExternalID);