Update libxml to 2.7.7.

third_party/libxml/error.c

Index: third_party/libxml/error.c
diff --git a/third_party/libxml/error.c b/third_party/libxml/error.c
index 5f03d940a2accacf46a1edd6100dc6001f1b2dcd..7508d41b074b488447ab474cdf2607e3938a2d9c 100644
--- a/third_party/libxml/error.c
+++ b/third_party/libxml/error.c
@@ -132,7 +132,7 @@ xmlSetGenericErrorFunc(void *ctx, xmlGenericErrorFunc handler) {
  */
 void
 xmlSetStructuredErrorFunc(void *ctx, xmlStructuredErrorFunc handler) {
-    xmlGenericErrorContext = ctx;
+    xmlStructuredErrorContext = ctx;
     xmlStructuredError = handler;
 }
 
@@ -471,7 +471,7 @@ __xmlRaiseError(xmlStructuredErrorFunc schannel,
 	 * if user has defined handler, change data ptr to user's choice
 	 */
 	if (schannel != NULL)
-	    data = xmlGenericErrorContext;
+	    data = xmlStructuredErrorContext;
     }
     if ((domain == XML_FROM_VALID) &&
         ((channel == xmlParserValidityError) ||
@@ -573,7 +573,6 @@ __xmlRaiseError(xmlStructuredErrorFunc schannel,
 	if ((to->file == NULL) && (node != NULL) && (node->doc != NULL)) {
 	    to->file = (char *) xmlStrdup(node->doc->URL);
 	}
-	file = to->file;
     }
     to->line = line;
     if (str1 != NULL)
@@ -593,20 +592,23 @@ __xmlRaiseError(xmlStructuredErrorFunc schannel,
     /*
      * Find the callback channel if channel param is NULL
      */
-    if ((ctxt != NULL) && (channel == NULL) && (xmlStructuredError == NULL) && (ctxt->sax != NULL)) {
+    if ((ctxt != NULL) && (channel == NULL) &&
+        (xmlStructuredError == NULL) && (ctxt->sax != NULL)) {
         if (level == XML_ERR_WARNING)
 	    channel = ctxt->sax->warning;
         else
 	    channel = ctxt->sax->error;
 	data = ctxt->userData;
     } else if (channel == NULL) {
-        if (xmlStructuredError != NULL)
+        if ((schannel == NULL) && (xmlStructuredError != NULL)) {
 	    schannel = xmlStructuredError;
-	else
+	    data = xmlStructuredErrorContext;
+	} else {
 	    channel = xmlGenericError;
-	if (!data) {
-	data = xmlGenericErrorContext;
-    }
+	    if (!data) {
+		data = xmlGenericErrorContext;
+	    }
+	}
     }
     if (schannel != NULL) {
         schannel(data, to);
@@ -927,6 +929,7 @@ xmlCtxtResetLastError(void *ctx)
 
     if (ctxt == NULL)
         return;
+    ctxt->errNo = XML_ERR_OK;
     if (ctxt->lastError.code == XML_ERR_OK)
         return;
     xmlResetError(&ctxt->lastError);