This was in pursuit of trying to get line numbers in `zig build run` on
macOS to work, but I wasn't able to figure that out and this wasn't the
right path because static libs can't have dsyms. But, it may still be
useful to make the xcframework step dsym aware for future use so I'm
PRing this.

`zig build run` on macOS now builds the app bundle via the `xcodebuild`
CLI and runs it. The experience for running the app is now very similar
to Linux or the prior GLFW build, where the app runs, blocks the zig
command, and logs to the terminal.

`xcodebuild` has its own build cache system that we can't really hook
into so it runs on every `zig build run` command, but it does cache and
I find its actually relatively fast so I think this is a good
replacement for the glfw-based system.