编译c-ares库从失败到成功的过程
c-ares-master: apt-get install libtool
https://github.com/c-ares/c-ares
==============================
失败的过程;
```
{
1.host配错了
./configure --host=x86_64-pokysdk-linux --target=arm-poky-linux-gnueabi --prefix=/root/work/lib_arm/c-ares
make
root@ubuntu:~/work/share/mqtt/c-ares-master# find . -name "*.so*"
./.libs/libcares.so.2.2.0
./.libs/libcares.so