diff --git a/pkgs/development/libraries/cctz/default.nix b/pkgs/development/libraries/cctz/default.nix
index 2930ffa61e3..832b070c883 100644
--- a/pkgs/development/libraries/cctz/default.nix
+++ b/pkgs/development/libraries/cctz/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub }:
+{ stdenv, fetchFromGitHub, darwin }:
 
 stdenv.mkDerivation rec {
   name = "cctz-${version}";
@@ -13,8 +13,14 @@ stdenv.mkDerivation rec {
 
   makeFlags = [ "PREFIX=$(out)" ];
 
+  buildInputs = stdenv.lib.optional stdenv.isDarwin darwin.apple_sdk.frameworks.Foundation;
+
   installTargets = [ "install_hdrs" "install_shared_lib" ];
 
+  postInstall = stdenv.lib.optionalString stdenv.isDarwin ''
+    install_name_tool -id $out/lib/libcctz.so $out/lib/libcctz.so
+  '';
+
   enableParallelBuilding = true;
 
   meta = with stdenv.lib; {
diff --git a/pkgs/development/libraries/poco/default.nix b/pkgs/development/libraries/poco/default.nix
index 68ddf5c91d1..e766657c19a 100644
--- a/pkgs/development/libraries/poco/default.nix
+++ b/pkgs/development/libraries/poco/default.nix
@@ -28,6 +28,5 @@ stdenv.mkDerivation rec {
     description = "Cross-platform C++ libraries with a network/internet focus";
     license = licenses.boost;
     maintainers = with maintainers; [ orivej ];
-    platforms = platforms.linux;
   };
 }