set : illegal option -o pipefail error while trying to upgrade pkg.

Hello.

I'm trying to upgrade as much as I can FreeBSD 10.4 because it is the only
one version that can compile some of the old arm 32 bit code I need to use
for one of my projects. As you already know,packages don't work at all,but
ports almost work. I was trying to install xfce4 from ports,but the
compilation stopped when it didn't accept this file :


http://distcache.FreeBSD.org/ports-distfiles/trousers-0.3.14.tar.gz


at this point,I decided to upgrade the system with :


# freebsd-update fetch
# freebsd-update install


and the ports tree with :


# portsnap fetch extract
# portsnap fetch update


At this point it asked me to update pkg,so I did :


# cd /usr/ports/ports-mgmt/pkg
# make


but unfortunately I got this error that I'm not able to fix :


set : illegal option -o pipefail


and I can't do anything anymore. I'm stuck here. Can someone help me to fix
it ? thanks.
-- 
Mario.