acm.ino:1:10: fatal error: usb/usb_host.h: No such file or directory #include "usb/usb_host.h" ^~~~~~~~~~~~~~~~ compilation terminated. exit status 1 Compilation error: usb/usb_host.h: No such file or directory

[mvschaefer]

where is the file usb/usb_host.h ? is it part of another library dependency?