emacs: disable native compilation on Darwin

The duplicate `rpath` issue prevents running Emacs on macOS 15.4 and
also breaks the build on that platform, blocking the channels. From
asking around, it seems like native compilation shouldn’t have
such a huge impact on performance as to not make this worth it as
a temporary hack to unblock security fixes and give us more time to
sort out a proper solution.

pkgs/applications/editors/emacs/make-emacs.nix

@@ -66,7 +66,11 @@
   zlib,
 
   # Boolean flags
-  withNativeCompilation ? stdenv.buildPlatform.canExecute stdenv.hostPlatform,
+
+  # FIXME: Native compilation breaks build and runtime on macOS 15.4;
+  # see <https://github.com/NixOS/nixpkgs/issues/395169>.
+  withNativeCompilation ?
+    stdenv.buildPlatform.canExecute stdenv.hostPlatform && !stdenv.hostPlatform.isDarwin,
   noGui ? false,
   srcRepo ? true,
   withAcl ? false,