match psutil platform detection might catch some edge cases

setup.py

@@ -23,7 +23,7 @@ install_requires = [
 ]
 
 # Add macOS-specific packages if on Darwin (macOS)
-if sys.platform == "darwin":
+if sys.platform.startswith("darwin"):
     install_requires.extend(
         [
             "mlx==0.15.1",