Use proper typedef for uint64_t

[pps83]

Depending on order of includes using define causes errors

[pps83]

Here's what it means to have this kind of define without this fix: you cannot include stdint.h/inttypes.h after this time_.h file for obvious reasons. Those headers define uint64_t and preprocessor will replace uint64_t with unsigned __int64. This obviously will produce compilation error.

With the change, if you have a typedef, those headers will simply make identical typedef. This won't produce errors and/or warnings.