diff --git a/pkgs/tools/text/gnugrep/default.nix b/pkgs/tools/text/gnugrep/default.nix
index 36012dc6f50..f06be1b7336 100644
--- a/pkgs/tools/text/gnugrep/default.nix
+++ b/pkgs/tools/text/gnugrep/default.nix
@@ -2,7 +2,7 @@
 
 let version = "2.7"; in
 
-stdenv.mkDerivation {
+stdenv.mkDerivation ({
   name = "gnugrep-${version}";
 
   src = fetchurl {
@@ -38,4 +38,4 @@ stdenv.mkDerivation {
   };
 
   passthru = {inherit pcre;};
-}
+} // (if libiconv != null then { NIX_LDFLAGS="-L${libiconv}/lib -liconv"; } else {}) )