Hello! If there are no objections, I’d like to change the default substitute URLs to just “https://mirror.hydra.gnu.org”.
Currently it’s “https://mirror.hydra.gnu.org https://hydra.gnu.org” (see config-daemon.ac), but the second URL is redundant and can only cause slowness (if a substitute is missing on the mirror, the other machine is queried but it likely lacks it as well.) Since guix-maintenance commit 539f7351d749e25c73e90877ea159d495ed4d4b0, mirror.hydra.gnu.org caches build logs as well, which removes the main reason for keeping hydra.gnu.org among the substitute URLs. Thoughts? Ludo’.
