提高编译器兼容性
#if !defined(NS_INLINE)
#if defined(__GNUC__)
#define NS_INLINE static __inline__ __attribute__((always_inline))
#elif defined(__MWERKS__) || defined(__cplusplus)
#define NS_INLINE static inline
#elif defined(_MSC_VER)
#define NS_INLINE static __inline
#elif TARGET_OS_WIN32
#define NS_INLINE static __inline__
#endif
#endif