This was solved in Ubuntu by a no-change rebuild of db5.3. A binNMU was scheduled for db5.3. However, the build logs for 5.3.28+dfsg2-5+b1, at least on armel [1] and armhf [2], still show:
checking for 64-bit integral type support for sequences... no checking for growing a file under an mmap region... no Ubuntu is further along in the time_t transition, so further investigation is needed as to which package causes the change in buld behaviour of db5.3. [1] https://buildd.debian.org/status/logs.php?pkg=db5.3&arch=armel [2] https://buildd.debian.org/status/logs.php?pkg=db5.3&arch=armhf
