They already hardly support POSIX-like programs on iOS and watchOS.
In what concerns macOS, UNIX certification is anyway only for CLI applications and daemons like software, stuff like graphics isn't part of UNIX trademark.
Fair enough. They surely don't support tcc directly anyway. So, what I really meant was "informal hacker community support" (probably on jail broken/rooted devices when/where applicable!), not "official company support" and I didn't mean to suggest zero work would be involved..Just not a complexity explosion like C++.
In what concerns macOS, UNIX certification is anyway only for CLI applications and daemons like software, stuff like graphics isn't part of UNIX trademark.
https://publications.opengroup.org/standards/unix/t101