When it comes to descent like that, it’s tricky. Ever heard of the Scotch-Irish? All Irish MacDonalds/McDonalds come from the Scottish clan, who moved to Ulster initially.
And in the Gaelic language (both Irish and Scottish forms), there is no abbreviation. Everything reads as “Mac”, as in “Mac Dhòmhnaill” (Scottish form; Irish form uses an acute accent over the “o”).
Ha! Like a true Freeper, you apparently keep debating and subtly changing the subject after having been shown to be incorrect!
Just don’t ever eat a McDonald’s hamburger with a bowl of Campbell’s soup.