title: native-audio sample in NDK build problem
body: <p>i have a problem when build native-audio sample in NDK.
  The main reason is "SLES/OpenSLES.h: No such file or directory"</p>
  
  <p>I have googled but i dont find any thing helpful.</p>
  
  <p>Please help me.</p>
  
  <p>Thanks in advance</p>