Replace platforms.linux with platforms.darwin for expressions that compile on darwin too (too restrictive platforms)

pkgs/development/python-modules/plyvel/default.nix

@@ -22,7 +22,7 @@ buildPythonPackage rec {
 
   meta = with stdenv.lib; {
     description = "Fast and feature-rich Python interface to LevelDB";
-    platforms = platforms.linux;
+    platforms = platforms.unix;
     homepage = https://github.com/wbolster/plyvel;
     license = licenses.bsd3;
   };