Arch Linux recently updated libnsgif from 0.2.1 to 1.0.0 and having read the header files the 1.0.0 is not backwards compatible. This project will eventually have to be updated.
Animated gifs are disabled on NixOS until this issue is resolved.
See here for more info: https://github.com/NixOS/nixpkgs/blob/194846768975b7ad2c4988bdb82572c00222c0d7/pkgs/applications/graphics/imv/default.nix#L19