So when introducing a new soname (no just a new package name), then one should move to time64 even on i386 ?
The problem with doing this is that 1. A reverse dependency may depend on more than one library that uses time_t in it's API. Said reverse dependency would not be able to be sanely built if libfoo uses 32-bit time_t in it's API and libbar uses 64-bit time_t in it's API. 2. If any of your reverse dependencies are libraries that expose time_t in their API they would have a similar problem.