Hi @RichCap123,
It might be that the CommandLineTools package was updated recently and the compiler is getting a wrong header search path. I think there are similar posts in the forum, e.g. ROOT 6.10/08 on macOS High Sierra compiling macro example.
If none of the issues already solved in the forum helps, you could try manually executing the compiler command line (first line after the make invocation in the second screenshot), and add -v to see the underlying cc1 command. The -I... arguments should give a hint on what is wrong/missing. If needs be, you can copy the cc1 command line here.
Cheers,
J.