Additional mat3 constructors added, global variable namespace collisions
for uniform and object color avoided via re-name.
Metal vertex format compatibility added for shaders wherein vertex data
goes through a double-conversion and cannot be implicitly converted during
Metal vertex assembly e.g. bitmasks passed directly as unsigned type in
shader interface for certain shader interfaces.
Authored by Apple: Michael Parkin-White
Ref T96261
Reviewed By: fclem
Differential Revision: https://developer.blender.org/D16433
d90a2b0ab7