refactor(scanner): use new array header for stack

[eed3si9n]

Problem

@psarna wrote in #404:

Without proper alignment, UBSAN will cause the program to fail at runtime with "illegal instruction" signal.

Solution

This cherry picks scanner change 2c5c1d2 from #398.

[amaanq]

thank you for cherry picking my work @eed3si9n, I intended to make it easier to review/split it up, but didn't have time. and thanks for the NPM release too!