Revert "bin/ootb: Use hardlinks over symlinks"•••This reverts commit edbf0c2ce376ce6672fbc94d861fe26081c46418.
After adding the "build/" directory to the top-level .gitignore file, it
stopped complaining about the symlinks.
bin/gc: Run GC for user-level Guix first•••When there is 0 bytes of disk left, GPG fails to run because it can't
create a lockfile it requires.
This way, we free space before needing GPG.
bin/free-port: Try random ports over sequential ones•••To diminish race-conditions where two separate processes call
free-port(1) and get the same port that is free at that time, but only
one is able to bind to it.