Clang is such a great compiler! Not.
Compilers have enhanced diagnostics for some kinds of "well known"
undeclared identifiers, telling you exactly which header you might have
forgotten to include. The reason why clang needs an option GCC doesn't
need is because clang's fixit suggestions, unlike GCC's actually
*changes the type of the error*, as a result of a fixit of all things.
After the fixit suggestion grants this error the right to be ignored,
we start having to add clang-specific options.
Follow-up to https://github.com/mesonbuild/meson/issues/9140
Upstream clang bug, which appears to be going nowhere:
https://github.com/llvm/llvm-project/issues/33905
d57ca7d2a2