C++: Add more missing variable declaration tests

cpp/ql/test/library-tests/ir/ir/ir.cpp

@@ -1933,6 +1933,20 @@ namespace missing_declaration_entries {
         Bar2<int> b;
         b.two_missing_variable_declaration_entries();
     }
+
+    template<typename T> struct Bar3 {
+
+        int two_more_missing_variable_declaration_entries() {
+            extern int g;
+            int z(float);
+            return g;
+        }
+    };
+
+    void test3() {
+        Bar3<int> b;
+        b.two_more_missing_variable_declaration_entries();
+    }
 }
 
 template<typename T> T global_template = 42;