xdg_utils: xdg-open: add $out to PATH

Otherwise, xdg-open cannot call xdg-mime and this does not work:

    "${pkgs.xdg_utils}/bin/xdg-open"

pkgs/tools/X11/xdg-utils/default.nix

@@ -46,6 +46,7 @@ stdenv.mkDerivation rec {
     xset()  { ${xset}/bin/xset      "$@"; }\
     perl()  { PERL5LIB=${perlPath} ${perlPackages.perl}/bin/perl "$@"; }\
     mimetype() { ${perlPackages.FileMimeInfo}/bin/mimetype "$@"; }\
+    PATH=$PATH:'"$out"'/bin\
     &#' -i "$out"/bin/*
 
     substituteInPlace $out/bin/xdg-open \