[shawnz]

So how do you tell the difference between the files having been licensed individually or only the whole compilation having been licensed?

Here is some of the license text:

> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software") [...]

That seems to me to indicate that it applies to the whole software package and not any single file (unless you could call that single file a "software" in its own right, maybe?)

Meanwhile, the text in each individual file only says this:

> Copyright (c) 2015 Andrew Kelley

> This file is part of zig, which is MIT licensed. See http://opensource.org/licenses/MIT

[dragonwriter]

> So how do you tell the difference between the files having been licensed individually or only the whole compilation having been licensed?

One way you could check is if each of the files has their own copyright and license notice, and the license notice includes, directly or by reference, terms which require preservation of the accompanying copyright notice.

[shawnz]

How can you be sure the license notice wasn't meant to apply to the project as a whole, as I imagine is overwhelmingly the more common intention? That is the obvious question here.