12e84c6378
This solves the problem of e.g. mutt not finding mail unless the user sets MAIL=/var/spool/mail/$USER. The default MAIL variable seems come from bash. Reasons for adding symlink instead of changing MAIL default in bash: - No need to rebuild world - FHS recommends /var/mail over /var/spool/mail anyway[1]. Better fix NixOS mail location than change MAIL in bash to something that doesn't work on non-NixOS (however unlikely that users run nixpkgs bash on a non-NixOS distro...). [1] http://www.pathname.com/fhs/pub/fhs-2.3.html#VARMAILUSERMAILBOXFILES