Preparing to unpack .../perl-modules_5.20.2-6ubuntu0.2_all.deb ...
Unpacking perl-modules (5.20.2-6ubuntu0.2) over (5.20.2-6) ...
Preparing to unpack .../libc6-dev_2.21-0ubuntu4.3_amd64.deb ...
Unpacking libc6-dev:amd64 (2.21-0ubuntu4.3) over (2.21-0ubuntu4) ...
dpkg: error processing archive /var/cache/apt/archives/libc6-dev_2.21-0ubuntu4.3_amd64.deb (--unpack):
 unable to make backup link of './usr/include/arpa/nameser.h' before installing new version: Input/output error