Properly add SDL mocks for macOS.

Use library in new subproject.

Define separate package for config code.

Correctly include portmidi in tests.

Add mocks for some SDL functions related to joysticks/gamepads.

Remove old portmidi dependency.

Remove old SDL dependency.

Put minIni, and bdd-for-c dependencies to subprojects dir.

Extract additional platform-specific imports to basic compatibility
header.

Add parameter names for config mock functions.

Ensure input test implementation is aligned to current input API.

Use modes for list teardown calls to prevent pollution of the tracked
calls.

Separate mock library from source.

Add modes for log mocks.

Put mocks to directory structure mimicking project structure.

Remove symlinks and make codebase use common modules instead.

Add tests for initialization and teardown for all input methods.

Add memory and data-related implementations for handling game data.

Use consistent integer types for mocks.

Properly mock video function dependencies.

Update input tests.

Implement tests for joystick axis, hat, and button events.

Add third-party mocks, specify mock files.

/? Do we need first-party mocks in their own files, or can we provide a
mock flag in the implementation files already?