Nix: Use nixos-unstable for nodejs on Linux

My Laptop uses the stable channel for the system by default, but also
has the unstable channel available for when I need it.  NodeJS 8 isn't
available on the stable channel, so manually import nixos-unstable.

Other machines shouldn't be affected, as they're using nixpkgs
unstable on other OSes.

1 files changed, 5 insertions, 1 deletions

diff --git a/nix/.config/nixpkgs/config.nix b/nix/.config/nixpkgs/config.nix
index dc4e40a2..11d704a9 100644
--- a/nix/.config/nixpkgs/config.nix
+++ b/nix/.config/nixpkgs/config.nix
@@ -1,11 +1,15 @@
 { pkgs }: {
   packageOverrides = super: let
     self = super.pkgs;
+    pkgsUnstable = if super.pkgs.stdenv.isLinux
+      then import <nixos-unstable> {}
+      else super.pkgs;
+
   in with self; rec {
     myEmacs = super.callPackage ./emacs.nix {
       emacs = if stdenv.isDarwin then emacs25Macport else emacs;
     };
-    nodejs = pkgs.nodejs-8_x;
+    nodejs = pkgsUnstable.nodejs-8_x;
   };
 
   allowUnfree = true;