提示错误
Call to undeclared function 'OSAtomicCompareAndSwapPtrBarrier'; ISO C99 and later do not support implicit function declarations
Conflicting types for 'OSAtomicCompareAndSwapPtrBarrier'
Declaration of 'OSAtomicCompareAndSwapPtrBarrier' must be imported from module 'Darwin.libkern.OSAtomic' before it is required
解决方法：
在Svga.pbobjc.m或者Svga.pbobjc.h文件中添加以下头文件：
#import <libkern/OSAtomic.h>
