PHP and oci8.so can't start, what am I doing wrong?

Question

PHP

debian+apache2+php5. You need to connect the Oracle database.
I downloaded instantclient 12G (I also tried 10G, there is no difference), I installed oci8 I did it
according to the manual php.net/manual/en/oci8.installation.php
The problem is, when installing oci8 manually or using pecl, I get an error:

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/lib/php5/20131226/oci8.so' - /usr/lib/php5/20131226/oci8.so: cannot open shared object file: No such file or directory in Unknown on line 0

The library goes to the pace through pecl, manually - / compilation folder / modules.
Trying to copy the library or giving ln -s doesn't help, but the error changes.

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/lib/php5/20131226/oci8.so' - /usr/lib/php5/20131226/oci8.so: undefined symbol: _emalloc_128 in Unknown on line 0

The question is - what was done wrong and how to put the library on the path it complains about?