use env var SWAYSOCK if available

or fall back to /tmp/sway-ipc.sock

sway/ipc.c

@@ -40,10 +40,13 @@ void init_ipc() {
 
 	struct sockaddr_un ipc_sockaddr = {
 		.sun_family = AF_UNIX,
-		// TODO: use a proper socket path
+		.sun_path = "/tmp/sway-ipc.sock"
-		.sun_path = "/tmp/sway.sock"
 	};
 
+	if (getenv("SWAYSOCK") != NULL) {
+		strncpy(ipc_sockaddr.sun_path, getenv("SWAYSOCK"), sizeof(ipc_sockaddr.sun_path));
+	}
+
 	unlink(ipc_sockaddr.sun_path);
 	if (bind(ipc_socket, (struct sockaddr *)&ipc_sockaddr, sizeof(ipc_sockaddr)) == -1) {
 		sway_abort("Unable to bind IPC socket");