I was able to solve the problem where fontconfig was not able to find libexpat by adding the following in my xplatform qmake.conf
QMAKE_LINK = $HOST-g++ -lts -L/opt/qt/qt5.9.1arm/lib -Wl,-rpath -Wl,/opt/qt/qt5.9.1arm/lib QMAKE_LINK_SHLIB= $HOST-g++ -lts -L/opt/qt/qt5.9.1arm/lib -Wl,-rpath -Wl,/opt/qt/qt5.9.1arm/lib