anchor.diff:    (:ai-primitive-type-triangle 4)
     (:ai-primitive-type-polygon 8))
   
  +#-old-assimp
   (cffi:defcfun ("aiApplyPostProcessing" ai-apply-post-processing) :pointer
     (p-scene :pointer)
     (p-flags :unsigned-int))
   
  +#-old-assimp
   (cffi:defcfun ("aiGetMaterialTextureCount" ai-get-material-texture-count) :unsigned-int
     (p-mat :pointer)
     (type ai-texture-type))
   
  +#-old-assimp
   (cffi:defcfun ("aiImportFileFromMemory" ai-import-file-from-memory) :pointer
     (p-buffer :pointer)
     (p-length :unsigned-int)
  
positive.code:   (c :float)
    (d :float))
  
  (cffi:defcfun ("aiTransformVecByMatrix3" ai-transform-vec-by-matrix-3) :void
    (vec :pointer)
    (mat :pointer))
  
  (cffi:defcfun ("aiTransformVecByMatrix4" ai-transform-vec-by-matrix-4) :void
    (vec :pointer)
    (mat :pointer))
  
  (cffi:defcfun ("aiDetachLogStream" ai-detach-log-stream) ai-return
    (stream :pointer))
  
  
negative.code:   (m-num-properties :unsigned-int)
    (m-num-allocated :unsigned-int))
  
  #-old-assimp
  (cffi:defcfun ("aiGetMaterialProperty" ai-get-material-property) ai-return
    (p-mat :pointer)
    (p-key :pointer)
  