[libxml2] Make HTML parser functions take const pointers

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 576912fa04e3cab5876d94a99a9a2bb60b5fd0d1
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Sat Jun 17 15:59:13 2017 +0200

    Make HTML parser functions take const pointers
    
    The 'cur' parameter of htmlParseDoc and htmlSAXParseDoc should be
    'const xmlChar *'.
    
    Fixes bug 770650.

 HTMLparser.c                |    5 +++--
 include/libxml/HTMLparser.h |    4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/HTMLparser.c b/HTMLparser.c
index 22ec576..e4f816e 100644
--- a/HTMLparser.c
+++ b/HTMLparser.c
@@ -6278,7 +6278,8 @@ htmlCreatePushParserCtxt(htmlSAXHandlerPtr sax, void *user_data,
  */
 
 htmlDocPtr
-htmlSAXParseDoc(xmlChar *cur, const char *encoding, htmlSAXHandlerPtr sax, void *userData) {
+htmlSAXParseDoc(const xmlChar *cur, const char *encoding,
+                htmlSAXHandlerPtr sax, void *userData) {
     htmlDocPtr ret;
     htmlParserCtxtPtr ctxt;
 
@@ -6317,7 +6318,7 @@ htmlSAXParseDoc(xmlChar *cur, const char *encoding, htmlSAXHandlerPtr sax, void
  */
 
 htmlDocPtr
-htmlParseDoc(xmlChar *cur, const char *encoding) {
+htmlParseDoc(const xmlChar *cur, const char *encoding) {
     return(htmlSAXParseDoc(cur, encoding, NULL, NULL));
 }
 
diff --git a/include/libxml/HTMLparser.h b/include/libxml/HTMLparser.h
index 551186c..1d4fec2 100644
--- a/include/libxml/HTMLparser.h
+++ b/include/libxml/HTMLparser.h
@@ -115,12 +115,12 @@ XMLPUBFUN htmlParserCtxtPtr XMLCALL
 XMLPUBFUN int XMLCALL
                        htmlParseDocument(htmlParserCtxtPtr ctxt);
 XMLPUBFUN htmlDocPtr XMLCALL
-                       htmlSAXParseDoc (xmlChar *cur,
+                       htmlSAXParseDoc (const xmlChar *cur,
                                         const char *encoding,
                                         htmlSAXHandlerPtr sax,
                                         void *userData);
 XMLPUBFUN htmlDocPtr XMLCALL
-                       htmlParseDoc    (xmlChar *cur,
+                       htmlParseDoc    (const xmlChar *cur,
                                         const char *encoding);
 XMLPUBFUN htmlDocPtr XMLCALL
                        htmlSAXParseFile(const char *filename,