src/jdk.jextract/share/classes/com/sun/tools/jextract/TypedefHandler.java

@@ -138,10 +138,20 @@
                  */
                 return null;
             }
         }
 
+        /*
+         * There are typedefs on built-in types like struct __va_list_tag. These
+         * are not exposed as declaration cursor for any headers, but are available
+         * from Type objects. We've to walk and check null file path to detect these
+         * Cursors and create Trees.
+         */
+        Utils.getBuiltinRecordTypes(tt.type()).forEach(c -> {
+            decls.add(treeMaker.createTree(c));
+        });
+
         decls.add(tt);
         return null;
     }
 
     // test main to manually check this visitor