diff --git a/src/MacVim/MMTextViewHelper.m b/src/MacVim/MMTextViewHelper.m
index f008dfc16e..d0ebcc4f4c 100644
--- a/src/MacVim/MMTextViewHelper.m
+++ b/src/MacVim/MMTextViewHelper.m
@@ -47,6 +47,7 @@ static float MMDragAreaSize = 73.0f;
 
 
 
+#if (MAC_OS_X_VERSION_MAX_ALLOWED > MAC_OS_X_VERSION_10_4)
     static BOOL
 KeyboardInputSourcesEqual(TISInputSourceRef a, TISInputSourceRef b)
 {
@@ -61,6 +62,7 @@ KeyboardInputSourcesEqual(TISInputSourceRef a, TISInputSourceRef b)
 
     return [as isEqualToString:bs];
 }
+#endif
 
 
 @implementation MMTextViewHelper