feat: functional single-threaded imports

src/main/wacc/backend/LabelGenerator.scala

@@ -18,7 +18,7 @@ private class LabelGenerator {
   }
 
   private def getLabel(target: CallTarget | RuntimeError): String = target match {
-    case Ident(v, _)       => s"wacc_$v"
+    case Ident(v, guid)       => s"wacc_${v}_$guid"
     case Builtin(name)     => s"_$name"
     case err: RuntimeError => s".L.${err.name}"
   }