[php-src] Issue #8308: The return value of mb_list_encodings() doesn't contain 'SJIS-win'

Issue: https://github.com/php/php-src/issues/8308 Comment Author: alexdowad @sji-il, thank you for the report. This change actually dates back to 2020; see e2459857af. Before that commit, SJIS-win was indeed treated as a separate encoding from CP932, but testing revealed that the behavior of SJIS-win and CP932 was exactly the same (i.e. all the same mappings). I think the first question here is: Was there actually some difference between SJIS-win and CP932 which I missed? Perhaps more importantly, *should there have been* some difference? If indeed there is no difference, do you still feel that mb_list_encodings should list the same legacy text encoding twice, under two different names? Or perhaps SJIS-win should be the primary name, and CP932 should be an alias? Regarding the BC issue, I'm sorry that this was not documented as a backwards-incompatible change. I think this is actually a change from PHP 7.4 to 8.0, not from 8.0 to 8.1 (but please correct me if that is wrong).