Modify `cmInstallGenerator` to have a `cmDiagnosticContext` instead of
just a `cmListFileBacktrace`. Create helpers to obtain a state capture
that includes `CMD_INSTALL_ABSOLUTE_DESTINATION`. Modify most subclasses
(namely, ones that have a `DESTINATION`) to use this new state capture.
This fixes a limitation identified when 39a56136a3 (Diagnostic: Add warn
or error on absolute install paths, 2026-03-25) added the aforementioned
diagnostic, that the install generator(s) no longer have access to the
diagnostic state as of the `install` invocation which ultimately caused
the diagnostic if that scope is not the top-most scope of the current
subdirectory.
Note that some of the generators which capture context have not actually
implemented the diagnostic yet.
Fix most snake_case identifiers in cmInstall* to use camelCase instead.
Also, update clang-tidy configuration to help with applying these
changes, though the relevant check remains off by default.
Run the `clang-format.bash` script to update all our C and C++ code to a
new style defined by `.clang-format`, now with "east const" enforcement.
Use `clang-format` version 18.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
Issue: #26123
`include-what-you-use` diagnostics, in practice, are specific to
the environment's compiler and standard library. Update includes
to satisfy IWYU for our CI job under Debian 12.
This presents value semantics for a stack of constant values.
Internally it shares ownership to avoid copies. Previously
this was implemented by `cmListFileBacktrace` explicitly,
but the approach can be re-used for other kinds of stacks.