The "-ify" or "-fy" suffix in English means "to make". For example, "amplify", "magnify", "terrify", etc.

https://en.wiktionary.org/wiki/-ify

So heapify literally means "make into a heap". Not only is the name correct, but it is a better name for an in-place operation than either of the terms you give:

* "build-heap" does not describe an in-place operation;
* "make-heap" is ambiguous in whether it is in-place or not.

But even if we agreed that the name needs to change to match text books (which text books?), since heapify is a public function, we cannot just change the name. We would have to keep the old name around for many, many years, possibly forever.