mariadb105-server will not build for systems lacking sbrk, and needs the patch-MDEV-15961 file that is also in mariadb103-server and mariadb104-server.
Thanks for reporting, adding the patch...
A commit references this bug: Author: brnrd Date: Sun Jul 19 20:19:56 UTC 2020 New revision: 542596 URL: https://svnweb.freebsd.org/changeset/ports/542596 Log: databases/mariadb105-server: Fix build for i386 * pet portlint * i386 requires gcc [1] * Fix stacktrace [2] PR: 247535 [1], 247957 [2] Reported by: Raymond Quakkelaar <r quakkelaar quaras nl> [1], Naram Qashat <cyberbotx cyberbotx com> [2] Changes: head/databases/mariadb105-server/Makefile head/databases/mariadb105-server/files/mysql-server.in head/databases/mariadb105-server/files/patch-MDEV-15961 head/databases/mariadb105-server/pkg-plist
Started out with a new port with as few as possible patches. Keep reporting when things are missing!
Just as an FYI, this is FINALLY fixed upstream, and will be in the next patch release of all MariaDB versions. https://jira.mariadb.org/browse/MDEV-15961