On macOS 13.x, pip install chromadb failed while building the hnswlib wheel with clang errors such as "unknown type name 'nullptr_t'" and "command '/usr/bin/clang' failed with exit code 1". Multiple users hit this across Python 3.9 through 3.11. The root cause was hnswlib compiling with native CPU-architecture flags that the toolchain could not handle, so the build blew up on Apple hardware regardless of Python version.