No. I the first directory, the headers are one folder deeper in a directory fully called

/usr/local/Cellar/libxml2/2.9.9_2/include/libxml2/libxml

In the second, the libraries are present.

> On 25 Sep 2019, at 17:47, mituharu@math.s.chiba-u.ac.jp wrote:
>
>> To the first:
>>
>> -I/usr/local/Cellar/libxml2/2.9.9_2/include/libxml2
>> -L/usr/local/Cellar/libxml2/2.9.9_2/lib -lxml2
>>
>> And the second:
>>
>> /usr/local/opt/libxml2/lib/pkgconfig
>
> Do you have header files and libraries in the directories
> shown in the first output?
>
>                                       YAMAMOTO Mitsuharu
>                               mituharu@math.s.chiba-u.ac.jp
>
>
>