diff --git a/lib/Basics/process-utils.h b/lib/Basics/process-utils.h
index 063511cc42..6282ae86ef 100644
--- a/lib/Basics/process-utils.h
+++ b/lib/Basics/process-utils.h
@@ -93,6 +93,7 @@ struct ExternalId {
   HANDLE _writePipe;
 
   ExternalId();
+  virtual ~ExternalId() {}
 };
 #endif