feat: Update to NixOS 18.03

As the subject says ...

This only includes some minor changes in configuration. Most
interestingly several packages that I used to have in this repository
as custom packages are now available in `nixos-unstable`.

Unfortunately they weren't included in NixOS 18.03 though ...

Either way, this is cleaner.

configuration.nix

@@ -67,5 +67,5 @@
   # compatible, in order to avoid breaking some software such as database
   # servers. You should change this only after NixOS release notes say you
   # should.
-  system.stateVersion = "17.09"; # Did you read the comment?
+  system.stateVersion = "18.03"; # Did you read the comment?
 }

packages.nix

@@ -5,20 +5,12 @@
 { config, pkgs, ... }:
 
 let unstable = import <nixos-unstable> { config.allowUnfree = true; };
-    rust-overlay = import nixpkgs-mozilla/rust-overlay.nix;
 in {
   # Configure the Nix package manager
   nixpkgs = {
-    overlays = [ rust-overlay ];
     config.allowUnfree = true;
     config.packageOverrides = oldPkgs: oldPkgs // {
       wallpapers = import ./pkgs/wallpapers.nix;
-
-      # Remove nix-mode from the Nix package as a workaround for
-      # https://github.com/NixOS/nixpkgs/issues/36372
-      nix = oldPkgs.nix.overrideAttrs (oldAttrs: rec {
-        postInstall = "rm -rf $out/share/emacs";
-      });
     };
   };
 
@@ -31,6 +23,7 @@ in {
     dnsutils
     exa
     fd
+    firefox-bin
     fish
     gcc
     git
@@ -40,7 +33,7 @@ in {
     gnumake
     gnupg
     google-cloud-sdk
-    firefox-bin
+    gopass
     htop
     i3lock
     iftop
@@ -67,6 +60,7 @@ in {
     spotify
     stdmanpages
     tdesktop
+    terraform_0_10
     tig
     tmux
     tree
@@ -87,16 +81,9 @@ in {
     # Unstable packages:
     unstable.numix-cursor-theme
     unstable.kontemplate
-
+    unstable.mq-cli
-    # Overlay packages:
-    (rustChannelOf { date = "2018-01-04"; channel = "stable"; }).rust # Rust 1.23.0
 
     # Custom packages:
-    (import pkgs/mq-cli.nix)
-    (import pkgs/nixfd.nix)
     (import pkgs/pulseaudio-ctl.nix)
-    (import pkgs/stern-bin.nix)
-    (import pkgs/terraform-bin.nix)
-    (import pkgs/gopass-bin.nix { inherit pkgs; })
   ];
 }

pkgs/gopass-bin.nix

@@ -1,25 +0,0 @@
-{ pkgs ? import <nixpkgs> {} }:
-
-with pkgs; stdenv.mkDerivation rec {
-  name = "gopass-bin-${version}";
-  version = "1.6.1";
-
-  src = fetchzip {
-    url = "https://github.com/justwatchcom/gopass/releases/download/v${version}/gopass-${version}-linux-386.tar.gz";
-    sha256 = "06iif74akcfb8n1h3ggig56a8y854p4dc7dpxpdfy6w9ra514phq";
-  };
-
-  phases = "installPhase";
-  installPhase = ''
-    mkdir -p $out/bin $out/share/fish/completions
-    cp $src/fish.completion $out/share/fish/completions/gopass.fish
-    cp $src/gopass $out/bin/gopass
-    chmod +x $out/bin/gopass
-  '';
-
-  meta = with stdenv.lib; {
-    description = "password-store like password manager with team functionality";
-    license     = licenses.mit;
-    homepage    = "https://github.com/justwatchcom/gopass";
-  };
-}

pkgs/mq-cli.nix

@@ -1,35 +0,0 @@
-# Build and install mq-cli.
-
-with import <nixpkgs> {};
-
-let
-  # The cached Cargo registry moves *very* slowly, override it:
-  newRegistry = rustRegistry.overrideAttrs (oldAttrs: rec {
-    name = "rustRegistry-2017-10-20";
-    src = fetchFromGitHub {
-      owner  = "rust-lang";
-      repo   = "crates.io-index";
-      rev    = "a1e85af8f57ba61e505c2cb2dc359b66caf355e9";
-      sha256 = "0xcszw287kqlz15ikflsim36mrvpvlb2y074vg22szz0r48nn06v";
-    };
-  });
-in rustPlatform.buildRustPackage rec {
-  name = "mqcli-${version}";
-  version = "0.1.0";
-
-  rustRegistry = newRegistry;
-  depsSha256 = "138a4dgwhf78bnmxz2ibxqz1wifq5046czxd0w8a4gwngy2ryiqs";
-
-  src = fetchFromGitHub {
-    owner  = "aprilabank";
-    repo   = "mq-cli";
-    rev    = "d908fe1cbc7de0bff7cadbe0b3851d50229b7de2";
-    sha256 = "0c4myav65dzks53q4grin9lhcz1jzpddqnihf2h9lm098dhrswkp";
-  };
-
-  meta = with stdenv.lib; {
-    description = "CLI interface to POSIX message queues";
-    homepage    = https://github.com/aprilabank/mq-cli;
-    license     = licenses.mit;
-  };
-}

pkgs/nixfd.nix

@@ -1,28 +0,0 @@
-with import <nixpkgs> {};
-
-# Build and install my nixfd tool.
-with rustPlatform;
-
-buildRustPackage rec {
-  name = "nixfd-${version}";
-  version = "0.1.0";
-
-  # This hash is of course total bullshit due to the dummy libc dependency
-  # caused by:
-  # https://github.com/NixOS/nixpkgs/issues/22737
-  depsSha256 = "0iihnyq50qbq0fkvcj5jxilcw7d3bwd1x3gwcq0mzrcah23say0j";
-
-  src = fetchFromGitHub {
-    owner = "tazjin";
-    repo = "nixfd";
-    rev = "dbadc9ef8486070f26677154fa032a47d732b7a9";
-    sha256 = "162301lc4znlqbansmaw9sla1rwi2s5nfmhl3z752n6aj2gcvz89";
-  };
-
-  meta = with stdenv.lib; {
-    description = "Tired of waiting for nix-env -qaP?";
-    homepage = https://github.com/tazjin/nixfd;
-    license = licenses.mit;
-    platforms = platforms.all;
-  };
-}

pkgs/stern-bin.nix

@@ -1,25 +0,0 @@
-with import <nixpkgs> {};
-
-stdenv.mkDerivation rec {
-  name = "stern-${version}";
-  version = "1.5.1";
-
-  src = fetchurl {
-    url = "https://github.com/wercker/stern/releases/download/${version}/stern_linux_amd64";
-    sha256 = "0xjxhgi1mlkbqimf0fk5cxr6lvwxrr2z49bnw4b1vqpd1gdqjyiv";
-    name = "stern";
-  };
-
-  phases = "installPhase";
-  installPhase = ''
-    mkdir -p $out/bin
-    cp $src $out/bin/stern
-    chmod +x $out/bin/stern
-  '';
-
-  meta = with stdenv.lib; {
-    description = "Multi pod and container log tailing for Kubernetes";
-    homepage = "https://github.com/wercker/stern";
-  };
-}
-

pkgs/terraform-bin.nix

@@ -1,26 +0,0 @@
-# Package to install a Terraform binary release.
-# This is necessary because the Terraform package on Nix does not currently
-# build for some reason.
-
-with import <nixpkgs> {};
-
-stdenv.mkDerivation rec {
-  name = "terraform-${version}";
-  version = "0.10.7";
-
-  src = fetchzip {
-    url = "https://releases.hashicorp.com/terraform/0.10.7/terraform_0.10.7_linux_amd64.zip";
-    sha256 = "189g94bb1d3wxzp720a5vki91czsqmk728469wa1fdkl43cdqd2n";
-  };
-
-  installPhase = ''
-    mkdir -p $out/bin
-    mv terraform $out/bin/terraform
-  '';
-
-  meta = with stdenv.lib; {
-    description = "Terraform is a tool for building, changing, and combining infrastructure safely and efficiently";
-    homepage = "https://www.terraform.io/";
-    license  = licenses.mpl20;
-  };
-}

pkgs/wallpapers.nix

@@ -5,8 +5,9 @@ stdenv.mkDerivation {
   name    = "tazjins-wallpapers-1";
 
   src = fetchgit {
-    url = "https://git.tazj.in/tazjin/wallpapers.git";
+    url    = "https://git.tazj.in/tazjin/wallpapers.git";
-    rev = "3bce73b605ba5f848cb4e7cc33058a2be3952c68";
+    rev    = "3bce73b605ba5f848cb4e7cc33058a2be3952c68";
+    sha256 = "1gjlazag7x005sf2bd6a7dw5p9ry5vjgzmvycsyiw3pv9b1gzc0j";
   };
 
   installPhase = ''