Add ccache to environment.systemPackages
diff --git a/src/system.nix b/src/system.nix
index aab1ade..19d9a83 100644
--- a/src/system.nix
+++ b/src/system.nix
@@ -295,6 +295,7 @@
     wob
     wlsunset
     cni-plugins
+    ccache
   ];
 
 #  environment.systemPackages = [