NPM inserts a default install script when a package has a `binding.gyp`
file.
It's possible, however, for the package to exclude the `binding.gyp`
file when they publish, and in this case the install script will never
succeed for a user of the package.
This happens with `fsevents`, for instance. They don't include the
`binding.gyp` file in their published tarball, but the default install
script appears in the manifest served by `npm`.
This causes us to warn that `fsevents` has an install script, but when
you try to run it it fails due to `binding.gyp` not existing.