Tiemo Jung
All CPU detection functions SDL_Has* will return false, even if it is supported by the CPU, if SDL is compiled with MSVC and the target is x64.
The reason for this is that 'CPU_haveCPUID' will return 0 and macro 'cpuid' in SDL_cpuinfo.c is the fallback implementation, which sets all params to zero.
It is safe to assume that cpuid is supported on a CPU that runs windows x64, so CPU_haveCPUID can just return 1, and the empty macro can be replaced with a small wrap around the __cpuid intrinsic.