How to set an AAPT flag in Eclipse?

Question

I am using Eclipse for Android development, instead of Android Studio. (I have my reasons; I can't use AS at the moment.)

Now I need to use VectorDrawableCompat at the moment. As mentioned in the section titled "First things first" here, we have to turn on an AAPT flag in order to use VectorDrawableCompat. Now in the post, the method mentioned is for Gradle (i.e. Android Studio):

android {
  defaultConfig {
    vectorDrawables.useSupportLibrary = true
  }
}

My question is that how do I set this AAPT flag in Eclipse?