Explicitly include android-support-v4

Test: make checkbuild tests
Change-Id: Ia62442e72e76fe031242d7ddf509b4055ac81259
diff --git a/Android.mk b/Android.mk
index fc15f32..99dde75 100644
--- a/Android.mk
+++ b/Android.mk
@@ -22,6 +22,7 @@
 LOCAL_STATIC_JAVA_LIBRARIES := android-common
 
 LOCAL_STATIC_ANDROID_LIBRARIES := \
+        android-support-v4 \
         android-support-v13
 
 LOCAL_SRC_FILES := $(call all-java-files-under, src) $(call all-renderscript-files-under, src)