I think that would be a bad idea in this specific case.
Why? Because for the majority of codebases, the time_t change won't require any work.
You'd be forcing a compiler error, and it would effectively say "Add -D_TIME_BITS=64. If you're doing something really weird with time_t then you may have to update your code too, but in 95% of the cases, you can just add that flag."
I think the compiler error might be warranted for something like "You are using a function that is 95% of the time insecure or wrong, please add -DGAPING_SECURITY_HOLE if you know what you're doing", but if the error really is just "add a flag, you do not need to think about your code probably", the library authors themselves might as well default it for you.
Why? Because for the majority of codebases, the time_t change won't require any work.
You'd be forcing a compiler error, and it would effectively say "Add -D_TIME_BITS=64. If you're doing something really weird with time_t then you may have to update your code too, but in 95% of the cases, you can just add that flag."
I think the compiler error might be warranted for something like "You are using a function that is 95% of the time insecure or wrong, please add -DGAPING_SECURITY_HOLE if you know what you're doing", but if the error really is just "add a flag, you do not need to think about your code probably", the library authors themselves might as well default it for you.