Alpine configures uClibc with COMPAT_ATEXIT, the need for which seems to have passed
In the uClibc 0.9.33.2 sources, extra/Configs/Config.in says:
config COMPAT_ATEXIT
bool “Old (visible) atexit Support”
help
Enable this option if you want to update from 0.9.28 to git/0.9.29,
else you will be missing atexit() until you rebuild all apps.
It looks like we can now safely disable this.
(from redmine: issue id 1917, created on 2013-05-19, closed on 2013-11-04)