message: Fix .aar building on Mac
  Use -R instead of -r when copying libs.
diff: @@ -72,12 +72,12 @@ zip -r $$origdir/$(location :{1}.aar) jni/*/*.so
  for src in headers:
  if flatten_headers:
  cmd += """
  - cp -rL $$origdir/$(location {0}) headers/$$(basename $(location {0}))
  + cp -RL $$origdir/$(location {0}) headers/$$(basename $(location {0}))
  """.format(src)
  else:
  cmd += """
  mkdir -p headers/$$(dirname $(location {0}))
  - cp -rL $$origdir/$(location {0}) headers/$(location {0})
  + cp -RL $$origdir/$(location {0}) headers/$(location {0})
  """.format(src)
  cmd += "zip -r $$origdir/$(location :{0}.aar) headers".format(name)
  