Missing libpq.so in postgresql v10

[Long Nguyen <nguyenxl@xxxxxxxxxxx>]

I got the postgresql 10 packages for Ubuntu 16.04 server from 

deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg main

I then installed postgresql v10 through

     apt-get install postgresql-10

The lib directory is /usr/lib/postgresql/10/lib. However I cannot find a libpq.so file in it. It is required by our commvault backup system.

I checked what postgresql packages were installed with 'dpkg -l |grep postgres" and it showed these

ii  postgresql-10

ii  postgresql-client-10

ii  postgresql-client-common

ii  postgresql-common

ii  postgresql-server-dev-10

Just wonder if I missed something here.

Thanks