[libxml2] Fix HTML parser with threads and --without-legacy

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 38f04779f7afd758db6210123ec0b64c489595c5
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Mon Aug 22 13:33:35 2022 +0200

    Fix HTML parser with threads and --without-legacy
    
    If the legacy functions are disabled, the default "V1" HTML SAX handler
    isn't initialized in threads other than the main thread.
    htmlInitParserCtxt would later use the empty V1 SAX handler, resulting
    in NULL documents.
    
    Change htmlInitParserCtxt to initialize the HTML SAX handler by calling
    xmlSAX2InitHtmlDefaultSAXHandler. This removes the ability to change the
    default handler but is more in line with the XML parser which
    initializes the SAX handler by calling xmlSAXVersion, ignoring the V1
    default handler.
    
    Fixes #399.

 HTMLparser.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)
---
diff --git a/HTMLparser.c b/HTMLparser.c
index 975099ca..ba886908 100644
--- a/HTMLparser.c
+++ b/HTMLparser.c
@@ -5056,8 +5056,7 @@ htmlInitParserCtxt(htmlParserCtxtPtr ctxt)
         htmlErrMemory(NULL, "htmlInitParserCtxt: out of memory\n");
        return(-1);
     }
-    else
-        memset(sax, 0, sizeof(htmlSAXHandler));
+    memset(sax, 0, sizeof(htmlSAXHandler));
 
     /* Allocate the Input stack */
     ctxt->inputTab = (htmlParserInputPtr *)
@@ -5116,11 +5115,9 @@ htmlInitParserCtxt(htmlParserCtxtPtr ctxt)
     ctxt->nodeInfoNr  = 0;
     ctxt->nodeInfoMax = 0;
 
-    if (sax == NULL) ctxt->sax = (xmlSAXHandlerPtr) &htmlDefaultSAXHandler;
-    else {
-        ctxt->sax = sax;
-       memcpy(sax, &htmlDefaultSAXHandler, sizeof(xmlSAXHandlerV1));
-    }
+    ctxt->sax = sax;
+    xmlSAX2InitHtmlDefaultSAXHandler(sax);
+
     ctxt->userData = ctxt;
     ctxt->myDoc = NULL;
     ctxt->wellFormed = 1;