Remove libusb.h include from libfreenect.h

typedef freenect_usb_context as void, as it is already for win32. That way,
we drop the need to have a properly installed developpement files of libusb
when we don't use it directly. This fix also partly the problem of
discrepancy between the include paths of libusb on freebsd and libusb-1.0

Signed-off-by: Nicolas Bourdaud <nicolas.bourdaud@gmail.com>

Author: nbourdau

include/libfreenect.h

@@ -156,13 +156,7 @@ struct _freenect_device;
 typedef struct _freenect_device freenect_device; /**< Holds device information. */
 
 // usb backend specific section
-#ifdef _WIN32
-  /* frees Windows users of the burden of specifying the path to <libusb-1.0/libusb.h> */
-  typedef void freenect_usb_context;
-#else
-  #include <libusb-1.0/libusb.h>
-  typedef libusb_context freenect_usb_context; /**< Holds libusb-1.0 specific information */
-#endif
+typedef void freenect_usb_context; /**< Holds libusb-1.0 context */
 //
 
 /// If Win32, export all functions for DLL usage

src/libfreenect.pc.in

@@ -5,7 +5,7 @@ includedir=${prefix}/@PROJECT_INCLUDE_INSTALL_DIR@
 
 Name: @CMAKE_PROJECT_NAME@
 Description: Interface to the Microsoft Kinect sensor device.
-Requires: libusb-1.0
+Requires.private: libusb-1.0
 Version: @PROJECT_APIVER@
 Libs: -L${libdir} -lfreenect
 Cflags: -I${includedir}