Chan_gsm_bt compilation error

I did everything according to the install guide. But still I get the same error:

make[1]: Leaving directory `/usr/src/asterisk/res' make[1]: Entering directory `/usr/src/asterisk/channels' make[1]: *** No rule to make target `', needed by `all'. Stop. make[1]: Leaving directory `/usr/src/asterisk/channels' make: *** [subdirs] Error 1

I’m running it on the latest build of Asterisk and on a Debian OS.

Does anyone had an idea what I’ve done wrong?

link channel: