Hi Bryce, I used the patch for LP#1885403 (also I found it at gentoo), and the build is ok. Attached is the log corresponding to that build. I hope it helps.
** Attachment added: "Sbuild log" https://bugs.launchpad.net/ubuntu/+source/postfix/+bug/1939353/+attachment/5522667/+files/postfix_3.5.6-1ubuntu2_amd64-2021-09-02T14%3A08%3A58Z.build -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1939353 Title: FTBFS 3.5.6-1build1 with gcc-11 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/postfix/+bug/1939353/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs