diff --git a/pkgs/servers/sql/postgresql/ext/postgis.nix b/pkgs/servers/sql/postgresql/ext/postgis.nix
index 81fbd41b46ab..5e38cb42d194 100644
--- a/pkgs/servers/sql/postgresql/ext/postgis.nix
+++ b/pkgs/servers/sql/postgresql/ext/postgis.nix
@@ -23,7 +23,8 @@ stdenv.mkDerivation rec {
     sha256 = "0pnva72f2w4jcgnl1y7nw5rdly4ipx3hji4c9yc9s0hna1n2ijxn";
   };
 
-  buildInputs = [ libxml2 postgresql geos proj gdal json_c protobufc libiconv ];
+  buildInputs = [ libxml2 postgresql geos proj gdal json_c protobufc ]
+                ++ stdenv.lib.optional stdenv.isDarwin libiconv;
   nativeBuildInputs = [ perl pkgconfig ];
   dontDisableStatic = true;