Use stdenvNoCC where possible

This makes them not rebuild when the compiler toolchain changes.

users/simon/modules/mpv.nix

@@ -1,7 +1,5 @@
 { config, pkgs, ... }:
 let
-  stdenv = pkgs.stdenv;
-
   mpv-prescalers = builtins.fetchGit {
     url = "https://github.com/bjin/mpv-prescalers";
     ref = "master";
@@ -25,7 +23,7 @@ let
     };
   };
 
-  pitchcontrol = (stdenv.mkDerivation rec {
+  pitchcontrol = (pkgs.stdenvNoCC.mkDerivation rec {
     name = "pitchcontrol.lua";
     scriptName = name;
 

users/simon/modules/programs.nix

@@ -1,6 +1,6 @@
 { config, lib, pkgs, ... }:
 let
-  waifu2x-photo-models = pkgs.stdenv.mkDerivation {
+  waifu2x-photo-models = pkgs.stdenvNoCC.mkDerivation {
     name = "waifu2x-photo-models";
 
     src = pkgs.fetchFromGitHub {

users/simon/modules/scripts.nix

@@ -1,6 +1,6 @@
 { pkgs, ... }:
 let
-  scripts = pkgs.stdenv.mkDerivation {
+  scripts = pkgs.stdenvNoCC.mkDerivation {
     name = "scripts";
 
     src = ../files/scripts;

users/simon/modules/sway.nix

@@ -3,7 +3,7 @@ let
   common = import ./common.nix;
   solarized = common.colorschemes.solarized;
 
-  wallpaper = pkgs.stdenv.mkDerivation {
+  wallpaper = pkgs.stdenvNoCC.mkDerivation {
     name = "wallpaper";
 
     src = pkgs.fetchurl {