title: How to configure the various PRODUCT_AAPT_ properties for AOSP?
body: <p>I'm looking for an explanation of the following AOSP build properties, what valid values are and how they affect the build and any related properties. I am aware of the system property <code>ro.sf.lcd_density</code> but I can't find any official documentation anywhere about these:</p>
  
  <pre><code>PRODUCT_AAPT_CONFIG
  PRODUCT_AAPT_PREF_CONFIG
  PRODUCT_AAPT_PREBUILT_DPI
  </code></pre>