Export include dir

Every user of this library adds external/lz4/lib to their
LOCAL_C_INCLUDES. Export it for them so that they don't need to hardcode
this path.

Change-Id: I66cfb947f78c3c13d001a21caa875263c0377d8f
diff --git a/lib/Android.mk b/lib/Android.mk
index 711fdcf..ff1ce7b 100644
--- a/lib/Android.mk
+++ b/lib/Android.mk
@@ -8,20 +8,24 @@
 LOCAL_MODULE := liblz4
 LOCAL_MULTILIB := both
 LOCAL_SRC_FILES := $(liblz4_src_files)
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
 include $(BUILD_HOST_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)
 LOCAL_MODULE := liblz4
 LOCAL_MULTILIB := both
 LOCAL_WHOLE_STATIC_LIBRARIES := liblz4
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
 include $(BUILD_HOST_SHARED_LIBRARY)
 
 include $(CLEAR_VARS)
 LOCAL_MODULE := liblz4
 LOCAL_SRC_FILES := $(liblz4_src_files)
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
 include $(BUILD_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)
 LOCAL_MODULE := liblz4
 LOCAL_WHOLE_STATIC_LIBRARIES := liblz4
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
 include $(BUILD_SHARED_LIBRARY)