When setting systemd environment, chain user PATH with preexisting one

src/udev_monitor.rs

@@ -155,6 +155,10 @@ fn set_environment() -> Environment {
                     if let Some((variable, value)) = var.split_once("=") {
                         if let Err(env::VarError::NotPresent) = env::var(variable) {
                             env::set_var(variable, value);
+                        } else if variable == "PATH" {
+                            let current_path = env::var("PATH").unwrap();
+                            let chained_path = format!("{}:{}", value, current_path);
+                            env::set_var("PATH", chained_path);
                         }
                     }
                 }