Cannot build

[paeifbnaeufbpae]

Cloned the repo, ran make install, got the following error back:

~/skhd $ make install
rm -rf ./bin
mkdir -p ./bin
clang src/skhd.c -std=c99 -Wall -O2 -framework Cocoa -framework Carbon -framework CoreServices -o bin/skhd
In file included from src/skhd.c:30:
src/service.h:136:9: error: call to undeclared function '_NSGetExecutablePath'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  136 |     if (_NSGetExecutablePath(exe_path, &exe_path_size) < 0) {
      |         ^

The readme says building requires "xcode-8 command-line tools". Does that mean >= 8 or == 8?

If == 8, how does one even downgrade their Xcode command-line tools version?

According to pkgutil --pkg-info=com.apple.pkg.CLTools_Executables, I'm on version 15.