d170c98d13
This will help a lot on ARM, where nix-collect-garbage erases gcc; then, any change to a small system config file requires rebuilding gcc again. I don't know why it does not happen on x86. Maybe it just pulls the gcc from hydra, if garbage is collected.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.