Resiliency of compile-db generation to undefined compiler variables

[lionel-]

E.g. OBJC might be undefined, leading to a "subscript out of bounds" warning. See https://digitalcourage.social/@rstub/112702119137929277

[sebffischer]

Not sure whether this is related, but I am trying to run clang-tidy in a github actions workflow and I try to build compile_commands.json in the CI by running pkgload:::generate_db().
This works locally, but in the CI (https://github.com/r-xla/pjrt/actions/runs/17445209058/job/49537847305?pr=83), I get:

Error: Error in cmp[[1]] : subscript out of bounds
Calls: <Anonymous> ... build_commands -> Reduce -> compilers -> vapply -> FUN
Execution halted
Error: Process completed with exit code 1.

[sebffischer]

My issue was solved by installing the pkgload dev version