[libxml2] Fix htmlTagLookup

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 7279d236364739a05657a8a614c15990eb08d0c6
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Thu May 6 10:37:07 2021 +0200

    Fix htmlTagLookup
    
    Fix regression introduced with b25acce8. Some users like libxslt may
    call the HTML output functions on documents with uppercase tag names,
    so we must keep case-insensitive string comparison.
    
    Fixes #248.

 HTMLparser.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/HTMLparser.c b/HTMLparser.c
index adefb3b5..b56363a3 100644
--- a/HTMLparser.c
+++ b/HTMLparser.c
@@ -1418,10 +1418,10 @@ htmlInitAutoClose(void) {
 
 static int
 htmlCompareTags(const void *key, const void *member) {
-    const char *tag = (const char *) key;
+    const xmlChar *tag = (const xmlChar *) key;
     const htmlElemDesc *desc = (const htmlElemDesc *) member;
 
-    return(strcmp(tag, desc->name));
+    return(xmlStrcasecmp(tag, BAD_CAST desc->name));
 }
 
 /**