Failing to compile sketchbook with the DigisparkKeyboard library on Android

[LordHelmii]

Hey,
I'm using the app ArduinoDroid (https://play.google.com/store/apps/details?id=name.antonsmirnov.android.arduinodroid2&hl=de) and a Digispark 16.5 attiny85.
Compiling works fine on Windows and Ubuntu, but since adding libaries is a bit different on Android, I had to add the DigisparkKeyboard library
(https://github.com/digistump/DigistumpArduino/tree/master/digistump-avr/libraries/DigisparkKeyboard)
manually to the ArduinoDroid/libraries folder, which worked fine. But when trying to compile, I get the following error in the file
https://github.com/digistump/DigistumpArduino/blob/master/digistump-avr/libraries/DigisparkKeyboard/usbdrv.c

In function 'usbInit':
/path/to/usbdrv.c:618: undefined reference to 'usbCrc16Append'
/path/to/usbdrv.c:618: undefined reference to 'usbCrc16Append'
collect2: error: Id returned 1 exit status
Return code is not 0


Unfortunatlely, there doesn't seem to be any logs and I can't copy the compilation-output. I will provide any further information if needed.