root@ext:~# apt-get install libmysqlclient-dev

root@ext:/mnt_old/usr/lib# ls -a | grep mysql
libmysqlclient.a
libmysqlclient.la
libmysqlclient_r.a
libmysqlclient_r.la
libmysqlclient_r.so
libmysqlclient_r.so.16
libmysqlclient_r.so.16.0.0
libmysqlclient.so
libmysqlclient.so.15
libmysqlclient.so.15.0.0
libmysqlclient.so.16
libmysqlclient.so.16.0.0
libmysqlserver.so.2
libmysqlserver.so.2.0
root@ext:/mnt_old/usr/lib#

root@ext:/usr/lib# ls -a | grep mysql
root@ext:/usr/lib#

root@ext:/usr/lib# apt-get install libmysqlclient-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
libmysqlclient-dev is already the newest version.
The following packages were automatically installed and are no longer required:
  gamin libgamin0 python-gamin python-support
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

/usr/lib/x86_64-linux-gnu