Squash 4.3

First release in 3 years brings Squash 4.3.

Please don’t merge this until #32755 is merged.
Squashfm 4.3

This will probably fail the bot, but I wanted to check my debug failure
locally matched the bot’s.
squashfs 4.3

Stole the patch from over
[here](https://github.com/plougher/squashfs-tools/pull/3) and manually
applied it to avoid the merge conflicts. Houston, We have build success.
Squashfs 4.3

Building with clang now seems to work thanks to the more comprehensive
patch, and I’ve added a better patch explanation because the last one
was hella lazy of me.
squashfs: add 4.3 bottle.