How to properly use ssh-askpass in Guix?

[Evgenii Klimov <eugene.dev@lipklim.org>]

Hi,

I tried to use Emacs' `vc-pull' and `vc-push' commands, but since my ssh
key is passphrase-protected it requires some kind of ssh-askpass type of
program.

From output I see that it tries to find ssh-askpass in openssh
directory, but there's nothing here (as far as I understand, ssh-askpass
is not part of openssh project directly):

    Running "git pull --stat"...
    ssh_askpass: exec(/gnu/store/78x0r0r72y865rkbs6vk78wmvd2404c0-openssh-9.8p1/libexec/ssh-askpass): No such file or directory

I guess each window manager offers its own variant of ssh-askpass, but I
use DWM, so I guess I need something WM independent.

I found x11-ssh-askpass package, but it doesn't provide any environment
variables or something to make the ssh process aware of it.

I get to use this package, binding SSH_ASKPASS variable myself, like:

    export SSH_ASKPASS="$(guix package -I x11-ssh-askpass | cut -f4)/libexec/ssh-askpass"

But it doesn't look clean to me.

Am I missing something, or is there a better way?  Or does this package
need a fix?