NTT: replace int64_t indexes with faster ptrdiff_t (MSVC don't accept size_t in OpenMP-accelerated cycles)
NTT: replace int64_t indexes with faster ptrdiff_t (MSVC don't accept size_t in OpenMP-accelerated cycles)

Bulat-Ziganshin/FastECC,Bulat-Ziganshin/FastECC,Bulat-Ziganshin/FastECC