This also partially reverts r326025 (8a16b7a18f). I do not see any
point of adding SPDX tag in generated file.
MFC after: 3 days
Submitted by: Dan McGregor <dan.mcgregor@usask.ca> (initial version)
Differential Revision: https://reviews.freebsd.org/D28596
Mainly focus on files that use BSD 3-Clause license.
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.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.