D3DXVECTOR2/3/4, D3DXMATRIX, D3DXQUATERNION, D3DXPLANE, D3DXCOLOR with
d3dx8math.inl operator semantics, plus the D3DX* functions the 2V3 slice
logic uses. Covered by port.common; port_gate passes on macOS, Android,
iOS and Windows (mingw).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>