Add -DVP_DEBUG in debug mode.

    * src/CMakeLists.txt.

src/CMakeLists.txt

@@ -11,7 +11,7 @@ INCLUDE_DIRECTORIES(
 IF (\"${CMAKE_VERBOSITY_LEVEL}\" STREQUAL \"\")
   ADD_DEFINITIONS(-DVP_DEBUG_MODE=0)
 ELSE (\"${CMAKE_VERBOSITY_LEVEL}\" STREQUAL \"\")
-  ADD_DEFINITIONS(-DVP_DEBUG_MODE=${CMAKE_VERBOSITY_LEVEL})
+  ADD_DEFINITIONS(-DVP_DEBUG_MODE=${CMAKE_VERBOSITY_LEVEL} -DVP_DEBUG)
 ENDIF (\"${CMAKE_VERBOSITY_LEVEL}\" STREQUAL \"\")
 
 ADD_LIBRARY(${LIBRARY_NAME}