Why did Marty mcfly go by Clint eastwood?

Marty McFly never went by Clint Eastwood in the Back to the Future movies. This is likely a misunderstanding or a joke.

* Marty McFly's name is Marty McFly.

* Clint Eastwood is a famous actor and director.

There is no mention of Marty McFly ever adopting Clint Eastwood's name or persona in the movies.