[OS X] Including problem with file keep_alive.c

[killkrt]

Please note that build process on OS X 10.9.2 gives the following error:

...
[ 3%] Building C object src/CMakeFiles/freenect.dir/keep_alive.c.o
/Users/killkrt/Development/3rdparty/libfreenect/src/keep_alive.c:68:10: fatal error:
'libusb-1.0/libusb.h' file not found

include <libusb-1.0/libusb.h>

...

To fix it I've simply replaced:

include < libusb-1.0/libusb >

with

include < libusb.h >

in file "src/keep_alive.c".

Thank you.