It's technically not specified by POSIX, but it appears most Unix-like
systems worth mentioning put those definitions there. Also, it's more
logical since the dev_t type is defined there.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
