The latest instant client libraries for Oracle are version 12.1:

http://www.oracle.com/technetwork/topics/linuxsoft-082809.html
http://www.oracle.com/technetwork/topics/linuxx86-64soft-092277.html

However, our ./configure script can only process versions up to 11.x:

$ ./configure --enable-server --with-oracle --with-oracle-include=/usr/include/oracle/12.1/client64/ --with-oracle-lib=/usr/lib/oracle/12.1/client64/lib/
...
checking for Oracle OCI headers in /usr/include/oracle/12.1/client64/... yes
checking if Oracle OCI version is >= 10.0... yes
checking for Oracle version >= 11.x to use -lnnz11 flag... yes
checking for Oracle OCI libraries in /usr/lib/oracle/12.1/client64/lib/... not found
checking if Oracle support is enabled... no
configure: error: Oracle OCI library not found