Returns the absolute path of the artifact to emit.
The filename to write into the output directory, beside the bundle.
The bare specifier the application imports, e.g. esbuild.
The environment variable the package reads at runtime to locate its artifact.
A dependency that loads a native artifact through a path relative to its own source, and so cannot survive being bundled. The artifact is emitted beside the bundle, and the package is pointed back at it by an environment variable set before the application starts.