add util_env

src/util_env.rs

@@ -0,0 +1,9 @@
+
+use std::env;
+
+pub fn is_env_on(var: &str) -> bool {
+    match env::var(var) {
+        Err(_) => false,
+        Ok(v) => (v == "TRUE" || v == "true" || v =="YES" || v == "yes" || v == "1"),
+    }
+}