these warnings are found by Clang-17 after removing
`-Wno-unused-lambda-capture` and '-Wno-unused-variable' from
the list of disabled warnings in `configure.py`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
After the mechanical change in fcb8d040e8
("treewide: use Software Package Data Exchange (SPDX) license identifiers"),
a few stray license blurbs or fragments thereof remain. In two cases
these were extra blurbs in code generators intended for the generated code,
in others they were just missed by the script.
Clean them up, adding an SPDX license identifier where needed.
Closes#10072
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
