ref: 0bdc6c0c61147a066982553e0a47896062f3deaa astr/.builds d---------
Install exact autoconf & automake packages on OpenBSD.

Specify the exact version numbers for these packages.
Adding environment variables for OpenBSD build.

Define the `AUTOCONF_VERSION` and `AUTOMAKE_VERSION` environment variables.
Added build for `openbsd/latest`.
Added build manifest for FreeBSD.

Building on `freebsd/latest` image.
Added build trigger to send email on failure.
Adding missing `cd` to fix build task.
Added build file for Debian stable.

Created `.builds` directory for `builds.sr.ht` and added Debian stable
build definition.