[tz] Version identification (was Re: Downstream use of 2021c)

[Paul Eggert]

On 10/7/21 13:00, Tom Lane via tz wrote:
> maybe
> there's something to be said for using +VERSION as the file name

Unfortunately the POSIX portable filename character set lacks '+'.

https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_282

Perhaps Apple used "+VERSION" so as to not collide with any portable 
filename.

Admittedly, installed filenames like "Etc/GMT+10" already use "+" and 
nobody seems to mind. Though perhaps the people who would mind are not 
using the "etcetera" file (as it's kinda optional) and thus are 
sidestepping the issue.