Actually, as I'm the one who bundled it in for RHEL4, I can assure you it is there. For example, running as root without Zimbra's Scalar::Util present, we get:
[root@build01 tmp]# perl /tmp/test.pl
is only avaliable with the XS version at /tmp/test.pl line 7
BEGIN failed--compilation aborted at /tmp/test.pl line 7.
Once Zimbra's Scalar::Util is present, we get success with both the zimbra and root user:
[root@build01 tmp]# perl /tmp/test.pl
[root@build01 tmp]# su - zimbra
[zimbra@build01 ~]$ perl /tmp/test.pl
[zimbra@build01 ~]$
Code:
#!/usr/bin/perl
use lib "/opt/zimbra/libexec";
use lib "/opt/zimbra/libexec/scripts";
use lib "/opt/zimbra/zimbramon/mrtg/lib/mrtg2";
use lib "/opt/zimbra/zimbramon/lib";
use lib "/opt/zimbra/zimbramon/lib/Zimbra";
use Scalar::Util qw/dualvar/;
This is with the 5.0.0 release installed on our RHEL4 box. You may be running into one of the various issues with using CentOS4 instead of RHEL4.
--Quanah