Update Android NDK version so I can keep using readlinkat
diff --git a/Application.mk b/Application.mk
index 4ef25f9..ef28524 100644
--- a/Application.mk
+++ b/Application.mk
@@ -1,3 +1,3 @@
 APP_BUILD_SCRIPT := $(call my-dir)/Android.mk
 APP_STL := stlport_static
-APP_PLATFORM := android-19
+APP_PLATFORM := android-21