Supersedes https://gitlab.winehq.org/wine/wine/-/merge_requests/8338
The header cannot seem to be generated easily from an IDL, gameinput has some unfortunate versioning which reuses the same identifiers across versions, in an incompatible way and sometimes sharing only a subset of them (for instance enum values), and uses C++ namespaces to separate versions.
The implementation needs to support every interface version at the same time, which is implemented by wrapping identifiers and adding version suffixes whenever it is included by the implementing code. The tests are also using that so we can tests multiple versions in the same file.
-- v6: dinput/tests: Add some gameinput tests. gameinput: Introduce new DLL. include: Add gameinput.idl.