diff --git a/pkgs/development/libraries/libpng/12.nix b/pkgs/development/libraries/libpng/12.nix
index b3f7f96e936..457f99ef13b 100644
--- a/pkgs/development/libraries/libpng/12.nix
+++ b/pkgs/development/libraries/libpng/12.nix
@@ -1,6 +1,8 @@
-{ stdenv, fetchurl, zlib }:
+{ stdenv, fetchurl, zlib
+, buildPlatform, hostPlatform
+}:
 
-assert !(stdenv ? cross) -> zlib != null;
+assert hostPlatform == buildPlatform -> zlib != null;
 
 stdenv.mkDerivation rec {
   name = "libpng-1.2.57";
@@ -16,7 +18,7 @@ stdenv.mkDerivation rec {
 
   passthru = { inherit zlib; };
 
-  crossAttrs = stdenv.lib.optionalAttrs (stdenv.cross.libc == "libSystem") {
+  crossAttrs = stdenv.lib.optionalAttrs (hostPlatform.libc == "libSystem") {
     propagatedBuildInputs = [];
     passthru = {};
   };