Build issue when starting SITL

I am currently experiencing the following problem when trying to start SITL. Looks like make cannot find the right target to build. Could anyone help me with this ?

sim_vehicle.sh -W
~/ardupilot/user ~
Building sitl
make: *** No rule to make target ‘sitl’. Stop.
make: *** No rule to make target ‘clean’. Stop.
make: *** No rule to make target ‘sitl’. Stop.
/home/user/ardupilot/Tools/autotest/sim_vehicle.sh: Build failed