[clang] [llvm] [Clang] Fix definition of layout-compatible to ignore empty classes (PR #92103)

[David Blaikie via llvm-commits]

dwblaikie wrote:

How's this compare with other implementations clang is trying to be compatible with (gcc (in the normal clang driver mode) and msvc (in clang-cl mode))? Would this be an ABI break against them, or is this intended as an ABI fix to align better with them? Or some third option?

https://github.com/llvm/llvm-project/pull/92103