Not sure why other dev-perl/ ebuilds do not complain here but ...
>>> Emerging (24 of 64) dev-perl/MailTools-2.80.0
* MailTools-2.08.tar.gz RMD160 SHA1 SHA256 size ;-) ... [ ok ]
>>> Unpacking source...
>>> Unpacking MailTools-2.08.tar.gz to /var/tmp/portage/dev-perl/MailTools-2.80.0/work
>>> Source unpacked in /var/tmp/portage/dev-perl/MailTools-2.80.0/work
>>> Preparing source in /var/tmp/portage/dev-perl/MailTools-2.80.0/work/MailTools-2.08 ...
>>> Source prepared.
>>> Configuring source in /var/tmp/portage/dev-perl/MailTools-2.80.0/work/MailTools-2.08 ...
* Using ExtUtils::MakeMaker
* perl Makefile.PL PREFIX=/usr INSTALLDIRS=vendor INSTALLMAN3DIR=none DESTDIR=/var/tmp/portage/dev-perl/MailTools-2.80.0/image/
Checking if your kit is complete...
Warning: prerequisite Test::Pod 1 not found.
Writing Makefile for Mail
>>> Source configured.
>>> Compiling source in /var/tmp/portage/dev-perl/MailTools-2.80.0/work/MailTools-2.08 ...
* emake OTHERLDFLAGS=-Wl,-O1 -Wl,--as-needed
make -j4 'OTHERLDFLAGS=-Wl,-O1 -Wl,--as-needed'
cp lib/Mail/Address.pm blib/lib/Mail/Address.pm
It installs fine, whether you want to add DEPEND line is up to you.
# emerge -pv dev-perl/MailTools
These are the packages that would be merged, in order:
Calculating dependencies... done!
[ebuild R ] dev-perl/MailTools-2.80.0 USE="-test" 0 kB
It complains because Test::Pod is listed in Makefile.PL. Other distributions don't list it in Makefile.PL.
MailTools only uses (well, it tries to use, ie it doesn't even fail if it is not installed,) this module during tests. If you enable tests, the ebuild will install Test::Pod.
So ignore the warning.
Upstream: "Better: I will move t/99pod.t to the (relatively new) xt/ directory"
Usptream says through https://rt.cpan.org/Public/Bug/Display.html?id=69918:
fixed in 2.09