client: support WAYLAND_SOCKET env var

[MaxVerevkin]

Closes #24

[MaxVerevkin]

@WhyNotHugo do you have an easy way to test this?

[WhyNotHugo]

import socket
import os
import subprocess

xdgrun = os.environ["XDG_RUNTIME_DIR"]
display = os.environ["WAYLAND_DISPLAY"]
socket_path = f"{xdgrun}/{display}"

sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
sock.connect(socket_path)
fd = sock.fileno()

new_env = os.environ.copy()
new_env.pop("WAYLAND_DISPLAY")
new_env["WAYLAND_SOCKET"] = str(fd) # Comment this line to confirm that WAYLAND_DISPLAY is really not used.

subprocess.run(["foot"], env=new_env, pass_fds=(fd,))

[WhyNotHugo]

This runs foot as a test program. Replace this with any program compiled with a patched wayrs.

[WhyNotHugo]

Tested with ./target/debug/examples/list_globals and seems to work fine 👍