Only consider `.o` and `.swiftmodule` inputs for now. Previously
we could end up with unnecessary dependencies for e.g plugin
dylibs, but we don't build and patch those in currently.
This enables the use of folder references for
compatible targets, allowing new source files to
be added without needing to regenerate the project.
Currently disabled by default; I'd like to get
some living-on before enabling.
This is a tool specifically designed to generate
Xcode projects for the Swift repo (as well as a
couple of adjacent repos such as LLVM and Clang).
It aims to provide a much more user-friendly experience
than the CMake Xcode generation (`build-script --xcode`).
