At the moment, glib assumes that if /etc/localtime is a symlink, that it's a symlink to zoneinfo file.
Toolbx containers add an extra layer of indirection though, making it a symlink to a symlink to a zoneinfo file.
This commit deals with the problem, by performing additional checks on /etc/localtime and ignoring it if those check fail, falling back instead to reading /etc/timezone.
Trivial backport of !2955 (merged) to glib-2-74.