lynx: enable default-colors

Building with this option allows Lynx to optionally use the default
colors of the terminal, when compiled with ncurses or slang. It does not
(as far as I know) change any default behavior.

Since we build with ncurses, I don't think there's any reason not to
have this.

pkgs/applications/networking/browsers/lynx/default.nix

@@ -23,6 +23,7 @@ stdenv.mkDerivation rec {
   hardeningEnable = [ "pie" ];
 
   configureFlags = [
+    "--enable-default-colors"
     "--enable-widec"
     "--enable-ipv6"
   ] ++ stdenv.lib.optional sslSupport "--with-ssl";