gh-92869: ctypes: Add c_time_t (#92870)

Adds `ctypes.c_time_t` to represent the C `time_t` type accurately as its size varies.

Primarily-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org> [Google]