John Mc Cain was born in the Panama Canal Zone. He was eligible but he didn’t win enough Electoral votes.
The US Code Title 8, Section 1401:
The following shall be Nationals and Citizens of the United States at Birth:
(g) a person born outside the geographical limits of the United States and its outlying possessions of parents one of whom is an alien, and the other a citizen of the United States who, prior to the birth of such person, was physically present in the United States or its outlying possessions for a period or periods totaling not less than five years, at least two of which were after attaining the age of fourteen years...
John McCain’s Father, accompanied by his mother, was in the US Navy and was on duty in the Panama Canal Zone. The soil of the US is always under the shoes of military personnel wherever they are assigned. No matter what line was crossed to insure his safe birth, John McCain was born to parents who stood on US soil.
(and I thoroughly dislike John McCain and his politics)
Be advised that John McCain, in any event, did not assume the Office of President so questions of his eligibility are moot.