'tools/run_in_bg.c:87: error: undefined reference to 'stderr'' with Android NDK 15b

Created by: fhahn

Building DyanmoRIO with the latest Android NDK (15b) fails with the following error

dynamorio/tools/run_in_bg.c:87: error: undefined reference to 'stderr'
dynamorio/tools/run_in_bg.c:157: error: undefined reference to 'stderr'
dynamorio/tools/run_in_bg.c:157: error: undefined reference to 'stdout'

Apparently the global variables for stderr and stdout have been removed from Bionic (https://stackoverflow.com/questions/39322852/android-ndk-undefined-reference-to-stderr)

Xref #1927, which describes another issue when building with recent NDK versions.