I cannot install the Oracle client for Perl using CPAN DBD:Oracle on Mac OSX.
It is needed to run the DBI connection service in Perl. 

How can I fix this?

The following errors occur -

```
 CPAN.pm: Going to build P/PY/PYTHIAN/DBD-Oracle-1.68.tar.gz

 Multiple copies of Driver.xst found in: /Library/Perl/5.12/darwin-thread-multi-2level/auto/DBI/       /System/Library/Perl/Extras/5.12/darwin-thread-multi-2level/auto/DBI/ at Makefile.PL line 39
 Using DBI 1.631 (for perl 5.012004 on darwin-thread-multi-2level) installed in  /Library/Perl/5.12/darwin-   thread-multi-2level/auto/DBI/

 Configuring DBD::Oracle for perl 5.012004 on darwin (darwin-thread-multi-2level)
 Trying to find an ORACLE_HOME
 Found /Library/Oracle/instantclient_11_2 /Library/Oracle/instantclient_11_2    /Library/Oracle/instantclient_11_2 /Library/Oracle/instantclient_11_2

 WARNING: Setting ORACLE_HOME env var to /Library/Oracle/instantclient_11_2 for you.
 WARNING: If these tests fail you may have to set ORACLE_HOME yourself!
 Installing on a darwin, Ver#12.0
 Using Oracle in /Library/Oracle/instantclient_11_2
 Can't find sqlplus. Pity, it would have helped.
 I'm having trouble finding your Oracle version number... trying harder

 WARNING: I could not determine Oracle client version so I'll just
 default to version 8.0.0.0. Some features of DBD::Oracle may not work.
 Oracle version based logic in Makefile.PL may produce erroneous results.
 You can use "perl Makefile.PL -V X.Y.Z" to specify a your client version.

 Oracle version 8.0.0.0 (8.0)
 DBD::Oracle no longer supports Oracle client versions before 9.2 
 Try a version before 1.25 for 9 and 1.18 for 8! at Makefile.PL line 271.
 Warning: No success on command[/usr/bin/perl Makefile.PL]
 PYTHIAN/DBD-Oracle-1.68.tar.gz
 /usr/bin/perl Makefile.PL -- NOT OK
 Running make test
 Make had some problems, won't test
 Running make install
 Make had some problems, won't install

```