Don't understand how to cache step output

I’m making a custom build step to execute godot --headless --dump-gdextension-interface and godot --headless --dump-extension-api which create files at the current working directory. They do not take an output file argument, nor will they output to stdout, so I can’t use std.Build.Step.Run. I made my own DumpGodotInterfaces step by referencing std/Build/Step/Run.zig and it does do what I want it to, and I can pass a LazyPath pointing to gdextension_interface.h to a TranslateC step. Now my probl...