flatpak temp font and icon fix

hosts/desktops/common/default.nix

@@ -3,6 +3,7 @@
 {
   imports = [
     ./boot.nix
+    ./flatpakfix.nix
     ./hardware.nix
     ./home-manager.nix
     ./impermanence.nix

hosts/desktops/common/flatpakfix.nix

@@ -0,0 +1,27 @@
+{ pkgs, config, ... }:
+
+{
+  # Using bindfs to create FHS font & icon directory
+  system.fsPackages = [ pkgs.bindfs ];
+  fileSystems = let
+    mkRoSymBind = path: {
+      device = path;
+      fsType = "fuse.bindfs";
+      options = [ "ro" "resolve-symlinks" "x-gvfs-hide" ];
+    };
+    aggregatedIcons = pkgs.buildEnv {
+      name = "system-icons";
+      paths = with pkgs; [ breeze-qt5 papirus-icon-theme ];
+      pathsToLink = [ "/share/icons" ];
+    };
+    aggregatedFonts = pkgs.buildEnv {
+      name = "system-fonts";
+      paths = config.fonts.packages;
+      pathsToLink = [ "/share/fonts" ];
+    };
+  in {
+    # Create an FHS mount to support flatpak host icons/fonts
+    "/usr/share/icons" = mkRoSymBind "${aggregatedIcons}/share/icons";
+    "/usr/share/fonts" = mkRoSymBind "${aggregatedFonts}/share/fonts";
+  };
+}