Build hamcrest against the SDK.

Change-Id: I986fed64e51db92d6c775688a6534d6aabecc7f1
diff --git a/Android.mk b/Android.mk
index 64c3f3c..a636bb0 100644
--- a/Android.mk
+++ b/Android.mk
@@ -34,6 +34,8 @@
 
 LOCAL_MODULE := hamcrest
 
+LOCAL_SDK_VERSION := 4
+
 LOCAL_MODULE_TAGS := optional
 
 include $(BUILD_STATIC_JAVA_LIBRARY)