Cannot find module with tag 'libjpeg' in import path

编译cocos2dx项目时提示错误：
$ cd ~/cocos2d-2.1beta3-x-2.1.0/HelloWorld/proj.android
$ ndk-build
Android NDK: /home/yc/cocos2d-2.1beta3-x-2.1.0/cocos2dx/Android.mk: Cannot find module with tag 'libjpeg' in import path   
Android NDK: Are you sure your NDK_MODULE_PATH variable is properly defined ?

网上找到解决办法：
$ cd ~/cocos2d-2.1beta3-x-2.1.0/HelloWorld/proj.android/jni
$ gedit Android.mk
在
$(call import-module,CocosDenshion/android) \
$(call import-module,cocos2dx) \
$(call import-module,extensions)
的前面加上：
$(call import-add-path,/home/yc/cocos2d-2.1beta3-x-2.1.0/)
$(call import-add-path,/home/yc/cocos2d-2.1beta3-x-2.1.0/cocos2dx/platform/third_party/android/prebuilt)
保存退出，重新编译，问题解决