Fix some libxml2 2.15.0 regressions

Author: dwarring

lib/LibXML/Raw.rakumod

@@ -884,8 +884,12 @@ class xmlXPathParserContext is export {
 
     has int32                 $.valueFrame; # used to limit Pop on the stack
 
+    #++ valuePush, valuePop renamed in libxml2 v2.15.0
     method valuePop(--> xmlXPathObject) is native($XML2) {*}
     method valuePush(xmlXPathObject --> int32) is native($XML2) {*}
+    #++ libxml2 v2.15.0+
+    method XPathPop(--> xmlXPathObject) is symbol('xmlXPathValuePop') is native($XML2) {*}
+    method XPathPush(xmlXPathObject --> int32)  is symbol('xmlXPathValuePush') is native($XML2) {*}
 }
 
 class anyNode is export does LibXML::Raw::DOM::Node {

lib/LibXML/XPath/Context.rakumod

@@ -325,7 +325,15 @@ method varLookupFunc returns Routine is rw {
 method registerFunctionNS(QName:D $name, Str $uri, &func, |args) {
     $!raw.RegisterFuncNS(
         $name, $uri,
-        -> xmlXPathParserContext $ctxt, Int $n {
+        self.config.version >= v2.15.00
+        ?? -> xmlXPathParserContext $ctxt, Int $n {
+            CATCH { default { $ctxt.XPathPush: callback-error($_) } }
+            my @params = reverse(self.get-value($ctxt.XPathPop) xx $n);
+            my $ret = &func(|@params, |args) // '';
+            my xmlXPathObject:D $out := xmlXPathObject.COERCE: $*XPATH-CONTEXT.park($ret, :$ctxt);
+            $ctxt.XPathPush($_) for $out;
+        }
+        !! -> xmlXPathParserContext $ctxt, Int $n {
             CATCH { default { $ctxt.valuePush: callback-error($_) } }
             my @params = reverse(self.get-value($ctxt.valuePop) xx $n);
             my $ret = &func(|@params, |args) // '';

t/02parse.t

@@ -743,10 +743,10 @@ subtest 'line numbers', {
     lives-ok { $doc = $parser.parse: :string( $goodxml ); };
 
     $root = $doc.documentElement();
-    is $root.line-number(), 0, "line number is 0";
+    is $root.line-number(), 0|2, "line number is 0";
 
     @kids = $root.childNodes();
-    is @kids[1].line-number(), 0, "line number is 0";
+    is @kids[1].line-number(), 0|3, "line number is 0";
 }
 
 subtest 'clean namespaces', {