Update NixOS build.

default.nix

@@ -2,24 +2,23 @@
 let
   pkgs = import <nixpkgs> {};
 in
-pkgs.stdenv.mkDerivation rec {
+pkgs.stdenv.mkDerivation {
   pname = "kte";
   version = "0.1.0";
 
   src = ./.;
 
-  nativeBuildInputs = [ pkgs.cmake ];
-  buildInputs = [ pkgs.ncurses ];
+  nativeBuildInputs = [ pkgs.cmake pkgs.pkg-config ];
+  buildInputs = with pkgs; [
+    ncurses
+    SDL2
+    libGL
+    xorg.libX11
+  ];
 
   cmakeFlags = [
+    "-DBUILD_GUI=ON"
     "-DCURSES_NEED_NCURSES=TRUE"
     "-DCURSES_NEED_WIDE=TRUE"
   ];
-
-  meta = with pkgs.lib; {
-    description = "A small terminal text editor";
-    license = licenses.mit;
-    platforms = platforms.linux;
-    mainProgram = "kte";
-  };
 }