dumbpipe: fix checkPhase with sandbox=relaxed on Darwin

dumbpipe's tests run the binary, which requires local network access.
dumbpipe also ends up invoking CoreFoundation APIs which require access
to system ICU data. [CoreFoundation will segfault if it cannot access
the system ICU data][1], so add these paths to the sandbox.

[1]: https://gist.github.com/al3xtjames/e8a260602c719bf35dae63988798e835

pkgs/by-name/du/dumbpipe/package.nix

@@ -19,6 +19,15 @@ rustPlatform.buildRustPackage rec {
   useFetchCargoVendor = true;
   cargoHash = "sha256-uuY0nh4VHzyM7+cbgyycr5I3IjE0OeQ0eg12qVXe4BQ=";
 
+  __darwinAllowLocalNetworking = true;
+
+  # On Darwin, dumbpipe invokes CoreFoundation APIs that read ICU data from the
+  # system. Ensure these paths are accessible in the sandbox to avoid segfaults
+  # during checkPhase.
+  sandboxProfile = ''
+    (allow file-read* (subpath "/usr/share/icu"))
+  '';
+
   meta = with lib; {
     description = "Connect A to B - Send Data";
     homepage = "https://www.dumbpipe.dev/";