diff --git a/contrib/xml2/xpath.c b/contrib/xml2/xpath.c
index a967257546..b999b1f706 100644
--- a/contrib/xml2/xpath.c
+++ b/contrib/xml2/xpath.c
@@ -74,8 +74,6 @@ pgxml_parser_init(PgXmlStrictness strictness)
 	/* Initialize libxml */
 	xmlInitParser();
 
-	xmlLoadExtDtdDefaultValue = 1;
-
 	return xmlerrcxt;
 }
 
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index f869c680af..3e24aba546 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -67,6 +67,16 @@
 #if LIBXML_VERSION >= 20704
 #define HAVE_XMLSTRUCTUREDERRORCONTEXT 1
 #endif
+
+/*
+ * libxml2 2.12 decided to insert "const" into the error handler API.
+ */
+#if LIBXML_VERSION >= 21200
+#define PgXmlErrorPtr const xmlError *
+#else
+#define PgXmlErrorPtr xmlErrorPtr
+#endif
+
 #endif							/* USE_LIBXML */
 
 #include "access/htup_details.h"
@@ -124,7 +134,7 @@ static xmlParserInputPtr xmlPgEntityLoader(const char *URL, const char *ID,
 										   xmlParserCtxtPtr ctxt);
 static void xml_errsave(Node *escontext, PgXmlErrorContext *errcxt,
 						int sqlcode, const char *msg);
-static void xml_errorHandler(void *data, xmlErrorPtr error);
+static void xml_errorHandler(void *data, PgXmlErrorPtr error);
 static int	errdetail_for_xml_code(int code);
 static void chopStringInfoNewlines(StringInfo str);
 static void appendStringInfoLineSeparator(StringInfo str);
@@ -2024,7 +2034,7 @@ xml_errsave(Node *escontext, PgXmlErrorContext *errcxt,
  * Error handler for libxml errors and warnings
  */
 static void
-xml_errorHandler(void *data, xmlErrorPtr error)
+xml_errorHandler(void *data, PgXmlErrorPtr error)
 {
 	PgXmlErrorContext *xmlerrcxt = (PgXmlErrorContext *) data;
 	xmlParserCtxtPtr ctxt = (xmlParserCtxtPtr) error->ctxt;