One possible improvement would be to append "t32" if you want 32-bit
time_t, instead of appending "t64" for 64-bit time_t. That way, people
wouldn't be stuck with appending that confusing "t64" for the
foreseeable future, and only specialists concerned with 32-bit time_t
would need to know about the issue.
Personally, I hope backward-compatibility concerns don't require this
sort of thing. I'd rather just switch, as Debian has.
I felt the same way about the 64-bit off_t back in the 1990s. It was
obvious to me even at the time that we would have been significantly
better off making off_t 64-bit, while keeping 32-bit off_t in the ABI
for backward compatibility; this is what NetBSD did with time_t in 2012.
Although I realize others felt differently, I never fully understood
their concerns.
And here I am, three decades later, still having to make changes[1] to
Autoconf's AC_SYS_LARGEFILE macro to continue to support that
30-year-old off_t mistake, and now with 64-bit time_t interacting with
64-off_t in non-orthogonal ways.
[1]:
https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=b71143738516017f0e0d347a4025301c06c40254
