app: fix darwin/arm build

Change-Id: I5ce658362ff24c7ed16a269eab7a5fcdcb5ad019
Reviewed-on: https://go-review.googlesource.com/12302
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/app/darwin_armx.go b/app/darwin_armx.go
index 8169025..57e4e78 100644
--- a/app/darwin_armx.go
+++ b/app/darwin_armx.go
@@ -120,10 +120,10 @@
 }
 
 //export sendTouch
-func sendTouch(touch, touchType uintptr, x, y float32) {
+func sendTouch(cTouch, cTouchType uintptr, x, y float32) {
 	id := -1
 	for i, val := range touchIDs {
-		if val == touch {
+		if val == cTouch {
 			id = i
 			break
 		}
@@ -131,7 +131,7 @@
 	if id == -1 {
 		for i, val := range touchIDs {
 			if val == 0 {
-				touchIDs[i] = touch
+				touchIDs[i] = cTouch
 				id = i
 				break
 			}
@@ -141,7 +141,7 @@
 		}
 	}
 
-	t := touch.Type(touchType)
+	t := touch.Type(cTouchType)
 	if t == touch.TypeEnd {
 		touchIDs[id] = 0
 	}