mtr: patch for "Error decoding localhost address"

pkgs/tools/networking/mtr/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, lib, fetchFromGitHub, autoreconfHook, pkgconfig
+{ stdenv, lib, fetchFromGitHub, fetchpatch, autoreconfHook, pkgconfig
 , libcap, ncurses
 , withGtk ? false, gtk2 ? null }:
 
@@ -14,6 +14,14 @@ stdenv.mkDerivation rec {
     rev    = "v${version}";
     sha256 = "0n0zr9k61w7a9psnzgp7xnc7ll1ic2xzcvqsbbbyndg3v9rff6bw";
   };
+  
+  patches = [
+    # https://github.com/traviscross/mtr/pull/315
+    (fetchpatch {
+      url = https://github.com/traviscross/mtr/pull/315.patch?full_index=1;
+      sha256 = "18qcsj9058snc2qhq6v6gdbqhz021gi5fgw9h7vfczv45gf0qasa";
+    })
+  ];
 
   # we need this before autoreconfHook does its thing
   postPatch = ''