Compiled PHP 7 missing mysql extension in WordPress

I have built PHP 7 with a configuration that worked for a previous version of PHP.
Now my WordPress websites get the message:

>Your PHP installation appears to be missing the MySQL extension which is required by WordPress.

Other websites using mysqli do work. What am I missing?

I've also included all .so files with mysql in the name:

extension=dba.so
extension=mysql.so
extension=mysqli.so
extension=mysqlnd_mysql.so
extension=mysqlnd_mysqli.so
extension=mysqlnd.so
extension=pdo.so
extension=pdo_mysql.so
extension=pdo_odbc.so
extension=odbc.so