use freetype for font display

nix/package.nix

@@ -9,6 +9,8 @@
   wayland-protocols,
   wayland-scanner,
   libxkbcommon,
+  freetype,
+  fontconfig,
   # Path to a replacement src/config.zig. dwm-style compile-time configuration:
   #   att_wm.override { configFile = ./my-config.zig; }
   # Deliberately not called `config`: callPackage would fill that from the
@@ -38,6 +40,8 @@ stdenv.mkDerivation {
     wayland-protocols
     wayland-scanner
     libxkbcommon
+    freetype
+    fontconfig
   ];
 
   zigBuildFlags = [