Change time_t to always-64-bit type
time_t is currently typedef'd in src/platform/types.rs as long (presumably following Linux' example). On platforms where long is 32 bits, this would make relibc susceptible to the year 2038 problem.
Since relibc/Redox currently does not support any 32-bit platforms, I suppose it would not be a breaking change to move to a redefinition as int64_t, at least for Redox. For eventual relibc compatibility with 32-bit Linux, we would need a platform-dependent time_t definition, or alternatively requiring kernel version 5.6+ (cf. this LKML post).
The BSDs have generally made the move to always-64-bit time_t.
Of course, such a change would need an accompanying change to the libc crate.