explicit cast to (long long). On *NIX we could get away with
lazily assuming time_t is of the same length as long (and use %ld),
even though the specification says nothing about it.
Unfortunately on Windows things are not that simple:
'time_t' is 'long long' (64 bits) and both 'int' and 'long'
are 32 bits, even when compiling in 64 bit mode.
This problem could be 'fixed' in multiple ways:
One way would be to minimize the usage of time_t and use 'long long'
or 'uint64_t' everywhere for variables to minimize casting later.
I, however, chose to maintain 'time_t' for most of time grabbing
and time calculations (eg: delta), and do the explicit cast in
any printf-like functions that may be there.
Both solutions work. I mostly like the explicit time_t look, so one
can immediately recognize a variable relates to time.