epic5: add configure flags

pkgs/applications/networking/irc/epic5/default.nix

@@ -1,5 +1,4 @@
-{stdenv, fetchurl, pkgs, openssl
-  , ncurses, libiconv, tcl }:
+{ stdenv, fetchurl, openssl, ncurses, libiconv, tcl }:
 
 stdenv.mkDerivation rec {
   name = "epic5-${version}";
@@ -11,17 +10,18 @@ stdenv.mkDerivation rec {
   };
 
   # Darwin needs libiconv, tcl; while Linux build don't
- 
   buildInputs = [ openssl ncurses ]
-   ++ stdenv.lib.optionals 
-   stdenv.isDarwin [ libiconv tcl ];
+    ++ stdenv.lib.optionals stdenv.isDarwin [ libiconv tcl ];
+
+  configureFlags = [ "--disable-debug" "--with-ipv6" ];
 
   postConfigure = ''
     substituteInPlace bsdinstall \
       --replace /bin/cp cp \
       --replace /bin/rm rm \
-      --replace /bin/chmod chmod \
+      --replace /bin/chmod chmod
   '';
+
   meta = with stdenv.lib; {
     homepage = "http://epicsol.org/";
     description = "a IRC client that offers a great ircII interface";