thenawaker@nawalight:~/bt/bluetooth$ make -C /lib/modules/$(uname -r)/build M=$(pwd) modules
make: Entering directory '/usr/src/linux-headers-4.5.0-040500rc4-generic'
  CC [M]  /home/thenawaker/bt/bluetooth/hci_h4.o
/home/thenawaker/bt/bluetooth/hci_h4.c: In function ‘h4_recv’:
/home/thenawaker/bt/bluetooth/hci_h4.c:128:8: error: implicit declaration of function ‘hci_recv_stream_fragment’ [-Werror=implicit-function-declaration]
  ret = hci_recv_stream_fragment(hu->hdev, data, count);
        ^
cc1: some warnings being treated as errors
scripts/Makefile.build:258: recipe for target '/home/thenawaker/bt/bluetooth/hci_h4.o' failed
make[1]: *** [/home/thenawaker/bt/bluetooth/hci_h4.o] Error 1
Makefile:1391: recipe for target '_module_/home/thenawaker/bt/bluetooth' failed
make: *** [_module_/home/thenawaker/bt/bluetooth] Error 2
make: Leaving directory '/usr/src/linux-headers-4.5.0-040500rc4-generic'