The goal is that all files of ValorC is just C with some extra annotations on top.
There should be an option where you can compile all ValorC files to C, and all of the annotations get turned into comments so that compilers like gcc and clang can compile ValorC programs.
fwiw using c attributes, so e.g. [[valorc::some_annotation]], c23 says:
For an attribute token (including an attribute prefixed token) not specified in this document, the behavior is implementation-defined. Any attribute token that is not supported by the implementation is ignored
so if you build the syntax on top of them, no transformation step should be needed