Ross Burton, thank you for the review.

The build reproduction steps and the intention for this patch can be found in the v1 patch at https://lists.openembedded.org/g/openembedded-core/topic/117252728.

PACKAGECONFIG:remove:class-native = "lto thin-lto"

Due to the configuration, llvm-native cannot enable lto in PACKAGECONFIG in any way.

When attempting to use clang + lto, components that cannot use the lld linker (and instead use the bfd linker) require the LLVMgold.so plugin.
To achieve this, binutils and the -DLLVM_BINUTILS_INCDIR flag in CMake are required.
(https://github.com/llvm/llvm-project/blob/main/clang/docs/ThinLTO.rst#basic)

Anyway, llvm-native cannot have LTO enabled due to the `remove`.

-DLLVM_ENABLE_LTO=Full determines whether LLVM itself will be built with LTO applied.

However, even if LLVM is not built using LTO, I think the environment should still be configured so that other components using the LLVM/clang toolchain can use LTO.