de93b32f90
The problem was that the non-fatal warning was not omitted from the output when constructing a nix expression. Now it seems OK for me. When return code is OK, the warnings don't get passed anywhere, but I expect that won't matter for this utility. Fatal errors are still shown.
*** 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.