anchor.diff:  
   /// Gets the error number
   int getErrorNumber() {
  +  _ensure();
     return getVariable("errno", "int").value;
   }
   
  
positive.code: 
  /// Invoke the system calls specified by [name] with the arguments specified by [args].
  dynamic invoke(String name, [List<dynamic> args = const [], List<BinaryType> vartypes]) {
    return LibC.invoke(name, args, vartypes);
  }
  
negative.code: 
  /// Initial Header
  const String HEADER = """
  typedef unsigned int size_t;
  typedef unsigned int mode_t;
  typedef unsigned int pid_t;
  typedef unsigned int uid_t;
  