diff --git a/Sources/_FoundationCShims/include/module.modulemap b/Sources/_FoundationCShims/include/module.modulemap
index 2f58a4244..30ff1ba76 100644
--- a/Sources/_FoundationCShims/include/module.modulemap
+++ b/Sources/_FoundationCShims/include/module.modulemap
@@ -1,4 +1,4 @@
-module _FoundationCShims {
+module _FoundationCShims [system] {
     header "_FoundationCShims.h"
 
     export *