But when I attempted to compile from a work-in-progress I had open from some months ago, I got this error:

Research suggests it might because I currently have an actual gcc installed via homebrew, due to the need to compile other software (which does not compile correctly with clang).
Is this actually the problem? If so, is there a way to get purebasic to use the tools it expects without having to uninstall the homebrew installed gcc?
If not, what else might be the cause of this?