Merge changes Icb5ba2a5,Ic5688a2c,I7c42aa37 am: 994929b524
am: 5572ea57fc

* commit '5572ea57fc434b239108d857af3948128b277ed6':
  Remove android-18/arm symbols not present in platform libc
  Remove LIBC_PRIVATE symbols from android-18 libm
  Remove LIBC_PRIVATE symbols from android-18 libc