This will soon be a dependency for machine/atomic.h on mips with the
introduction of 64-bit atomics; the scope here is pretty narrow, so throw it
here in the header just before systm.h, which includes machine/atomic.h
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.