diff --git a/app/darwin_armx.go b/app/darwin_armx.go
index 5541304..cd3f31b 100644
--- a/app/darwin_armx.go
+++ b/app/darwin_armx.go
@@ -24,6 +24,7 @@ import "C"
 import (
 	"log"
 	"runtime"
+	"sync"
 	"unsafe"
 
 	"golang.org/x/mobile/event"