I have opened a trivial pull request that fixes Klipper C code compilation under macOS: Makefile: Use C preprocessor from the target toolchain by dottedmag · Pull Request #6422 · Klipper3d/klipper · GitHub — could anyone of developers have a look, please?
It fixes a bug reported here: Klipper fails to build with Apple's cpp · Issue #6421 · Klipper3d/klipper · GitHub