Pixhawk6C Rover Build error in wsl

I am experiencing the following error when trying to build for a pixhawk6C flight controller.

./waf configure --board Pixhawk6C (works fine)
./waf rover, outputs the following error:
In file included from …/…/libraries/APM_Control/AR_AttitudeControl.cpp:22:
…/…/libraries/…/Rover/sailboat.h:110:5: error: ‘RC_Channel’ does not name a type
110 | RC_Channel *channel_mainsail; // rc input channel for controlling mainsail
| ^~~~~~~~~~
compilation terminated due to -Wfatal-errors.

Waf: Leaving directory `/home/ruben/ardupilot/build/fmuv3’
Build failed
→ task in ‘objs/APM_Control’ failed (exit status 1):
{task 139833481185536: cxx AR_AttitudeControl.cpp → AR_AttitudeControl.cpp.0.o}
(run with -v to display more information)

Can anybody help?