Manally add Box2D user lib and include paths

CMake succeeds, but make does not.

modules/FindBox2D.cmake

@@ -20,6 +20,8 @@ FIND_LIBRARY(BOX2D_LIBRARY NAMES ${BOX2D_NAMES})
 MARK_AS_ADVANCED(BOX2D_LIBRARY BOX2D_INCLUDE_DIR)
 
 # Per-recommendation
+SET(BOX2D_INCLUDE_DIR "/usr/local/include/")
+SET(BOX2D_LIBRARIE    "/usr/local/lib/")
 SET(BOX2D_INCLUDE_DIRS "${BOX2D_INCLUDE_DIR}")
 SET(BOX2D_LIBRARIES    "${BOX2D_LIBRARY}")