xsel doesn't dump binary (screenshot) data

[anatoly techtonik]

xsel ignores binary data in clipboard.

$ maim -s | xclip -selection clipboard -t image/png
$ xclip -o -selection clipboard > 1xclip
$ xsel -o --clipboard > 1xsel
$ ls -go 1*
-rw-rw-r-- 1 11948 Sep 26 20:13 1xclip
-rw-rw-r-- 1 0 Sep 26 20:13 1xsel

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xsel 1.2.0-4
ProcVersionSignature: Ubuntu 4.15.0-35.38-generic 4.15.18
Uname: Linux 4.15.0-35-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: i3
Date: Wed Sep 26 20:16:36 2018
SourcePackage: xsel
UpgradeStatus: Upgraded to bionic on 2018-08-05 (51 days ago)