ttygif: add missing dependencies on xwd, imagemagick

pkgs/tools/misc/ttygif/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub }:
+{ stdenv, fetchFromGitHub, makeWrapper, imagemagick, xorg }:
 
 stdenv.mkDerivation rec {
   pname = "ttygif";
@@ -13,6 +13,12 @@ stdenv.mkDerivation rec {
 
   makeFlags = [ "CC:=$(CC)" "PREFIX=${placeholder "out"}" ];
 
+  nativeBuildInputs = [ makeWrapper ];
+  postInstall = ''
+    wrapProgram $out/bin/ttygif \
+      --prefix PATH : ${stdenv.lib.makeBinPath [ imagemagick xorg.xwd ]}
+  '';
+
   meta = with stdenv.lib; {
     homepage = "https://github.com/icholy/ttygif";
     description = "Convert terminal recordings to animated gifs";