curlbuild.h:138:36: error: ‘socklen_t’ does not name a type

linux下调用libcurl.so时报错

解决：在引用curl.h之前添加socklen_t的引用，即#include <sys/socket.h>或
#include <unistd.h>

参考：https://blog.youkuaiyun.com/q454955979/article/details/72903463