add ccache

fake_flake.nix

@@ -59,6 +59,9 @@ in
     distro = "${distroName} ${version} (${codeName}) ${system}";
   };
 
+  nix.settings.extra-sandbox-paths = [ config.programs.ccache.cacheDir ];
+  programs.ccache.enable = true;
+
   environment.systemPackages =
     with pkgs;
     with lib;

overlays/ccache-wrapper.nix

@@ -0,0 +1,31 @@
+{
+  final,
+  prev,
+  config,
+  ...
+}:
+{
+  ccacheWrapper = prev.ccacheWrapper.override {
+    extraConfig = ''
+      export CCACHE_COMPRESS=1
+      export CCACHE_DIR="${config.programs.ccache.cacheDir}"
+      export CCACHE_UMASK=007
+      if [ ! -d "$CCACHE_DIR" ]; then
+        echo "====="
+        echo "Directory '$CCACHE_DIR' does not exist"
+        echo "Please create it with:"
+        echo "  sudo mkdir -m0770 '$CCACHE_DIR'"
+        echo "  sudo chown root:nixbld '$CCACHE_DIR'"
+        echo "====="
+        exit 1
+      fi
+      if [ ! -w "$CCACHE_DIR" ]; then
+        echo "====="
+        echo "Directory '$CCACHE_DIR' is not accessible for user $(whoami)"
+        echo "Please verify its access permissions"
+        echo "====="
+        exit 1
+      fi
+    '';
+  };
+}

overlays/default.nix

@@ -21,5 +21,6 @@
         ./deskwhich.nix
         ./mcontrolcenter.nix
         ./the-powder-toy.nix
+        ./ccache-wrapper.nix
       ];
 }

overlays/matrix-appservice-discord.nix

@@ -1,20 +1,20 @@
 { final, prev, ... }:
 {
   matrix-appservice-discord = prev.matrix-appservice-discord.overrideAttrs (old: {
-        src = prev.fetchFromGitHub {
-          owner = "t2bot";
-          repo = "matrix-appservice-discord";
-          rev = "8361ca6121bf1f0902154baa538cb6d5766e477f";
-          hash = "sha256-oXon6pFJgqQ1uBLtsSVNH7XSOpxxJYqpW2n9cFrs3sU=";
-        };
-        patches =
-          (
-            let
-              oldPatches = old.patches or [ ];
-            in
-            if oldPatches == null then [ ] else oldPatches
-          )
-          ++ [ ./patches/bridge_perms.patch ];
-        doCheck = false;
-      });
+    src = prev.fetchFromGitHub {
+      owner = "t2bot";
+      repo = "matrix-appservice-discord";
+      rev = "8361ca6121bf1f0902154baa538cb6d5766e477f";
+      hash = "sha256-oXon6pFJgqQ1uBLtsSVNH7XSOpxxJYqpW2n9cFrs3sU=";
+    };
+    patches =
+      (
+        let
+          oldPatches = old.patches or [ ];
+        in
+        if oldPatches == null then [ ] else oldPatches
+      )
+      ++ [ ../patches/bridge_perms.patch ];
+    doCheck = false;
+  });
 }

patches/lix-ccache.patch

@@ -0,0 +1,22 @@
+diff --git a/package.nix b/package.nix
+index 0186b7472..da783e152 100644
+--- a/package.nix
++++ b/package.nix
+@@ -1,7 +1,7 @@
+ {
+   pkgs,
+   lib,
+-  stdenv,
++  ccacheStdenv,
+   aws-sdk-cpp,
+   # If the patched version of Boehm isn't passed, then patch it based off of
+   # pkgs.boehmgc. This allows `callPackage`ing this file without needing to
+@@ -81,6 +81,8 @@ let
+   inherit (__forDefaults) canRunInstalled;
+   inherit (lib) fileset;
+ 
++  stdenv = ccacheStdenv;
++
+   version = lib.fileContents ./.version + versionSuffix;
+ 
+   aws-sdk-cpp-nix = aws-sdk-cpp.override {