Turn off auto optimise store on mac (#542)

* Disable auto-optimise-store on Mac

* Add comment on why we disable something

* fmt

* Auto-allocate-uids is linux only too

README.md

@@ -32,9 +32,9 @@ Differing from the current official [Nix](https://github.com/NixOS/nix) installe
 * In `nix.conf`:
   + the `auto-allocate-uids`, `nix-command` and `flakes` features are enabled
   + `bash-prompt-prefix` is set
-  + `auto-optimise-store` is set to `true`
+  + `auto-optimise-store` is set to `true` (On Linux only)
   * `extra-nix-path` is set to `nixpkgs=flake:nixpkgs`
-  * `auto-allocate-uids` is set to `true`.
+  * `auto-allocate-uids` is set to `true`.  (On Linux only)
 * an installation receipt (for uninstalling) is stored at `/nix/receipt.json` as well as a copy of the install binary at `/nix/nix-installer`
 * `nix-channel --update` is not run, `~/.nix-channels` is not provisioned
 * `NIX_SSL_CERT_FILE` is set in the various shell profiles if the `ssl-cert-file` argument is used.

src/action/common/place_nix_configuration.rs

@@ -50,7 +50,11 @@ impl PlaceNixConfiguration {
                 let _ = slot.insert(experimental_features.join(" ").to_string());
             },
         };
+
+        // https://github.com/DeterminateSystems/nix-installer/issues/449#issuecomment-1551782281
+        #[cfg(not(target_os = "macos"))]
         settings.insert("auto-optimise-store".to_string(), "true".to_string());
+
         settings.insert(
             "bash-prompt-prefix".to_string(),
             "(nix:$name)\\040".to_string(),