Add an environment variable to distinguish check

Author: fee1-dead

crates/project_model/src/build_scripts.rs

@@ -69,6 +69,8 @@ impl WorkspaceBuildScripts {
             }
         }
 
+        cmd.env("IS_RA_BUILDSCRIPT_CHECK", "1");
+
         // --all-targets includes tests, benches and examples in addition to the
         // default lib and bins. This is an independent concept from the --targets
         // flag below.