diff --git a/pkgs/development/libraries/avahi/default.nix b/pkgs/development/libraries/avahi/default.nix
index 7730e403d58..0789ef0ea7c 100644
--- a/pkgs/development/libraries/avahi/default.nix
+++ b/pkgs/development/libraries/avahi/default.nix
@@ -1,5 +1,5 @@
 { fetchurl, stdenv, pkgconfig, libdaemon, dbus, perl, perlXMLParser
-, expat, gettext, intltool, glib, qt4 ? null, lib
+, expat, gettext, intltool, glib, qt4 ? null, libiconvOrEmpty
 , qt4Support ? false
 , withLibdnssdCompat ? false }:
 
@@ -16,7 +16,8 @@ stdenv.mkDerivation rec {
   patches = [ ./no-mkdir-localstatedir.patch ];
 
   buildInputs = [ libdaemon dbus perl perlXMLParser glib expat ]
-    ++ (lib.optional qt4Support qt4);
+    ++ (stdenv.lib.optional qt4Support qt4)
+    ++ libiconvOrEmpty;
 
   buildNativeInputs = [ pkgconfig gettext intltool ];
 
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index e789ce87a3c..2844d47a501 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4084,9 +4084,11 @@ let
 
   libiconv = callPackage ../development/libraries/libiconv { };
 
+  libiconvOrEmpty = if (libiconvOrNull == null) then [] else libiconv;
+
   libiconvOrNull = if gcc ? libc then null else libiconv;
 
-  libiconvOrLibc = if gcc ? libc then gcc.libc else libiconv;
+  libiconvOrLibc = if (libiconvOrNull == null) then gcc.libc else libiconv;
 
   libid3tag = callPackage ../development/libraries/libid3tag { };