upx not found in PATH when upx-ucl is installed

[rjvkn]

On the current image, upx-ucl installs upx-ucl but not an upx binary, so tools expecting upx fail:

tssh -i id_ed25519 -p 2222 127.0.0.1
Warning: Permanently added '127.0.0.1:2222' (ssh-ed25519) to the list of known hosts.
catcher$ link --goos windows --garble --upx --lzma --name x.exe
upx could not be found in PATH

Could we add a symlink so upx resolves to upx-ucl?

Proposed Dockerfile change:

RUN apt install -y upx-ucl gcc-mingw-w64
RUN ln -s /usr/bin/upx-ucl /usr/local/bin/upx

Happy to open a PR if you’re OK with this.

[NHAS]

Ah thats a bit silly isnt it.

Im happy with either changing the binary to be upx-ucl, or to do the symlink. And also happy for you do open a PR to get your name associated with the fix, thanks for finding it!

[rjvkn]

Yep — exactly. Even though Docker is the recommended path, this repo still exposes server/client binaries, so it can be used outside Docker too.

That’s why I went with a portable runtime fix: resolve upx first, then fall back to upx-ucl, and run whichever exists. This keeps --upx working across both Docker and non-Docker environments, without baking Debian-specific naming into the code.

[NHAS]

Howdy.

Thanks for the pr!

Looks good and I've merged it into unstable for testing.