targets/darwin: copy fonts to ~/Library/Fonts/HomeManager (#1817)

Fonts are copied instead of being symlinked because macOS won't
recognize symlinked fonts.

modules/targets/darwin/default.nix

@@ -19,7 +19,7 @@ let
   writableDefaults = filterAttrs (domain: attrs: attrs != { }) nonNullDefaults;
   activationCmds = mapAttrsToList toActivationCmd writableDefaults;
 in {
-  imports = [ ./keybindings.nix ./linkapps.nix ./search.nix ];
+  imports = [ ./fonts.nix ./keybindings.nix ./linkapps.nix ./search.nix ];
 
   options.targets.darwin.defaults = mkOption {
     type = types.submodule ./options.nix;

modules/targets/darwin/fonts.nix

@@ -0,0 +1,27 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  homeDir = config.home.homeDirectory;
+  fontsEnv = pkgs.buildEnv {
+    name = "home-manager-fonts";
+    paths = config.home.packages;
+    pathsToLink = "/share/fonts";
+  };
+  fonts = "${fontsEnv}/share/fonts";
+in {
+  # macOS won't recognize symlinked fonts
+  config.home.activation.copyFonts = hm.dag.entryAfter [ "writeBoundary" ] ''
+    copyFonts() {
+      rm -rf ${homeDir}/Library/Fonts/HomeManager || :
+
+      local f
+      find -L "${fonts}" -type f -printf '%P\0' | while IFS= read -rd "" f; do
+        $DRY_RUN_CMD install $VERBOSE_ARG -Dm644 -T \
+          "${fonts}/$f" "${homeDir}/Library/Fonts/HomeManager/$f"
+      done
+    }
+    copyFonts
+  '';
+}