apacheHttpdPackages.mod_wsgi: enable on darwin

pkgs/servers/http/apache-modules/mod_wsgi/default.nix

···
     homepage = "https://github.com/GrahamDumpleton/mod_wsgi";
     description = "Host Python applications in Apache through the WSGI interface";
     license = lib.licenses.asl20;
-    platforms = lib.platforms.linux;
+    platforms = lib.platforms.unix;
   };
 }