Use was_invoked_from_cargo method instead of hand-written one

compiler/rustc_lint/src/non_local_def.rs

@@ -83,7 +83,7 @@ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
             if let Some(def_id) = oexpn.macro_def_id
                 && let ExpnKind::Macro(macro_kind, macro_name) = oexpn.kind
                 && def_id.krate != LOCAL_CRATE
-                && std::env::var_os("CARGO").is_some()
+                && rustc_session::utils::was_invoked_from_cargo()
             {
                 Some(NonLocalDefinitionsCargoUpdateNote {
                     macro_kind: macro_kind.descr(),

tests/ui/lint/non_local_definitions.rs

@@ -1,7 +1,7 @@
 //@ check-pass
 //@ edition:2021
 //@ aux-build:non_local_macro.rs
-//@ rustc-env:CARGO=/usr/bin/cargo
+//@ rustc-env:CARGO_CRATE_NAME=non_local_def
 
 #![feature(inline_const)]
 #![warn(non_local_definitions)]