In debian/rules: use_system_harfbuzz=1 \
also, the harfbuzz is installed, pine64user@debianpine64:~/chromium-browser-50.0.2661.75$ dpkg -l | grep harfbuzz ii libharfbuzz-dev:arm64 1.2.6-1 arm64 Development files for OpenType text shaping engine ii libharfbuzz-gobject0:arm64 1.2.6-1 arm64 OpenType text shaping engine ICU backend (GObject library) ii libharfbuzz-icu0:arm64 1.2.6-1 arm64 OpenType text shaping engine ICU backend ii libharfbuzz0b:arm64 1.2.6-1 arm64 OpenType text shaping engine (shared library) Not sure why it is not detected properly then.
