poppler: add nss to allow for building pdfsig

pkgs/development/libraries/poppler/default.nix

@@ -4,7 +4,7 @@
 , qt4Support ? false, qt4 ? null
 , qt5Support ? false, qtbase ? null
 , introspectionSupport ? false, gobjectIntrospection ? null
-, utils ? false
+, utils ? false, nss ? null
 , minimal ? false, suffix ? "glib"
 , hostPlatform
 }:
@@ -31,6 +31,7 @@ stdenv.mkDerivation rec {
     ++ optionals (!minimal) [ cairo lcms curl ]
     ++ optional qt4Support qt4
     ++ optional qt5Support qtbase
+    ++ optional utils nss
     ++ optional introspectionSupport gobjectIntrospection;
 
   nativeBuildInputs = [ pkgconfig ];
@@ -65,7 +66,9 @@ stdenv.mkDerivation rec {
     description = "A PDF rendering library";
 
     longDescription = ''
-      Poppler is a PDF rendering library based on the xpdf-3.0 code base.
+      Poppler is a PDF rendering library based on the xpdf-3.0 code
+      base. In addition it provides a number of tools that can be
+      installed separately.
     '';
 
     license = licenses.gpl2;