Blender Git Loki

Windows: Clean-up warning while building blendthumb

Casting a 64 bit pointer to a 32 bit DWORD gave 2 warnings.
Solved by storing the actual DWORD in the registry table.

Would have preferred to use a union, but C++ doesn't let you
initialize anything other than the first field, and C99 style
initializers are not supported until C++20, so this solution
will have to do until then.