(/mnt)/usr/share/zoneinfo in a listbox, and setting (/mnt)/etc/localtime
accordingly.
* Adjust for the needed menuc change un run.c's log_flip() and script_flip()
functions.
Related PRs:
5777 sysinst does not offer to tweak /etc/localtime
8099 changing the default time zone is non-obvious
9910 sysinst doesn't ask about setting timezone