This makes it so `zig build run` can take arguments such as
`--config-default-files=false` or any other configuration. Previously,
it only accepted commands such as `+version`.
Incidentally, this also makes it so that the app in general can now take
configuration arguments via the CLI if it is launched as a new instance
via `open`. For example:
open -n Ghostty.app --args --config-default-files=false
This previously didn't work. This is kind of cool.
To make this work, the libghostty C API was modified so that
initialization requires the CLI args, and there is a new C API to try to
execute an action if it was set.
`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.
