enables -Zexport-llvm-symbols only when stage1/2

Author: sgasho

src/bootstrap/src/core/build_steps/compile.rs

@@ -1261,7 +1261,7 @@ pub fn rustc_cargo(
         cargo.rustflag("-Zdefault-visibility=protected");
     }
 
-    if builder.config.llvm_enzyme && target.contains("apple") {
+    if builder.config.llvm_enzyme && target.contains("apple") && build_compiler.stage != 0 {
         cargo.rustflag("-Zexport-llvm-symbols");
     }