If you aren’t interested in working through all of the warnings-turned-errors, then I’d suggest just removing the -Werror from the Makefile and building.
But be cautioned that running on MacOS isn’t a thing that’s done frequently, and there’s signs that it might need some love. A previous MacOS thread suggests that simulation is probably still crashing, which means actually doing development on MacOS would first require fixing simulation, and there’s a bug report open for crashes in fdbcli as well.
I’d suggest building and developing via Docker for Mac with the provided Dockerfile.