Add global define for the clang compiler, and leave non-member 'fltx4' operator functions out when using clang to compile the SDK as these are causing errors. 'fltx4' is a typedef of __m128; not a user defined class, so these operators couldn't be added.
Unfortunately clang-cl doesn't support __FUNCTION__ macro concat. Some SSE stuff in mathlib/navmesh rendering also needs to be made portable at some point.
SourceSDK mathlib port with light modifications.
Renamed Vector to Vector3D (to avoid confusion with std::vector (declared as vector) and Vector2D/Vector4D).
