~emersion/mrsh

ref: job-control mrsh/.builds d---------
ci: add an optimized build
ci: migrate source repos to sr.ht
Switch FreeBSD build to freebsd/latest
ci: fix freebsd build
Add editline support
Add meson option for readline
ci: enable email on failure for FreeBSD
ci: add email triggers on failure
ci: split build and test tasks
ci: add ubsan
ci: add archlinux for ASAN

It looks like libasan isn't available on Alpine.
ci: enable address sanitizer for GCC builds
ci: run tests
ci: add FreeBSD