Adding GNU readline 6.3 apart

I set bashInteractive to use it, as it has many relevant fixes.

pkgs/development/libraries/readline/readline6.3.nix

@@ -0,0 +1,49 @@
+{ fetchurl, stdenv, ncurses }:
+
+stdenv.mkDerivation (rec {
+  name = "readline-6.3";
+
+  src = fetchurl {
+    url = "mirror://gnu/readline/${name}.tar.gz";
+    sha256 = "0hzxr9jxqqx5sxsv9vmlxdnvlr9vi4ih1avjb869hbs6p5qn1fjn";
+  };
+
+  propagatedBuildInputs = [ncurses];
+
+  patchFlags = "-p0";
+
+  patches =
+    [ ./link-against-ncurses.patch ];
+
+  meta = {
+    description = "GNU Readline, a library for interactive line editing";
+
+    longDescription = ''
+      The GNU Readline library provides a set of functions for use by
+      applications that allow users to edit command lines as they are
+      typed in.  Both Emacs and vi editing modes are available.  The
+      Readline library includes additional functions to maintain a
+      list of previously-entered command lines, to recall and perhaps
+      reedit those lines, and perform csh-like history expansion on
+      previous commands.
+
+      The history facilites are also placed into a separate library,
+      the History library, as part of the build process.  The History
+      library may be used without Readline in applications which
+      desire its capabilities.
+    '';
+
+    homepage = http://savannah.gnu.org/projects/readline/;
+
+    license = "GPLv3+";
+
+    maintainers = [ stdenv.lib.maintainers.ludo ];
+  };
+}
+
+//
+
+# Don't run the native `strip' when cross-compiling.
+(if (stdenv ? cross)
+ then { dontStrip = true; }
+ else { }))