refactor: wrap std::env::remove_var() in unsafe block

Author: SteveLauC

src/env.rs

@@ -49,7 +49,7 @@ pub unsafe fn clearenv() -> std::result::Result<(), ClearEnvError> {
         } else {
             use std::env;
             for (name, _) in env::vars_os() {
-                env::remove_var(name);
+                unsafe { env::remove_var(name); }
             }
             let ret = 0;
         }