Major Description
When running a fresh build on MacOs, thirdparty builds can fail with:
++ pkg-config --cflags openssl Package openssl was not found in the pkg-config search path. Perhaps you should add the directory containing `openssl.pc' to the PKG_CONFIG_PATH environment variable No package 'openssl' found + OPENSSL_CFLAGS=
A know workaround is to set the following:
export PKG_CONFIG_PATH=/usr/local/opt/openssl/lib/pkgconfig
We should document or automate this workaround in our builds.