message: makefile: fix invalid assignment to `virtual` property
diff: @@ -1370,12 +1370,9 @@ class BaseNode(object, metaclass = _BaseNodeType):
  return False
  def makefile_name(self):
  - if isinstance(self, Node):
  - return str(self.path())
  - else:
  - res = Path(self.name())
  - res.virtual = False
  - return str(res)
  + path = self.path() if isinstance(self, Node) \
  + else Path(self.name(), virtual = False)
  + return str(path)
  def makefile(self, marks = None):
  """Print a Makefile for this node."""
  