Pretty sure Adventure beat out Pac-Man for being the first ported game, being that it was ported back in '77, before Pac-Man first went to arcades.

https://en.wikipedia.org/wiki/Colossal_Cave_Adventure

Note that Pong and Space War were both ported before Pac-Man, as well, though Space War didn't get a home version before Pac-Man to my knowledge, it did get ported from mainframe hardware to an arcade cabinet before Pac-Man existed.