交叉编译问题： impossible constraint in 'asm
在进行交叉编译MQTT的时候 出现了一些问题
参考了http://zhangjunxin520.blog.163.com/blog/static/30503703201227103553401/
报错了
发现了
cc1: warning: include location "/usr/include" is unsafe for cross-compilation [-Wpoison-system-directories]
cc1: warning: include location "/usr/include" is unsafe for cross-compilation [-Wpoison-system-directories]
需要打开Makefile 把连接的头问题路径里面去掉
在make 就可以通过了