In libc++ starting with LLVM8 there's `<version>` include in `cstddef`:
The following things also align:
* QEMU has a file called `VERSION` in repo root
* QEMU prepends repo root to include path in build
* macOS has a case-insensetive filesystem
All of this combined means that `VERSION` file is included as a header.
Working around this be renaming `VERSION` -> `QEMU_VERSION` to resolve ambiguity.
The problem really only appears on `aarch64-darwin`, since on `x86_64-darwin`
there are no C++ files to compile. The workaround is harmless enough to apply.
d29e8f0e59