Bug#1000830: /usr/bin/which: this version of `which' is deprecated; use `command -v' in scripts instead.

[積丹尼 Dan Jacobson]

# strace --output=/tmp/xx -ff  dpkg -i /var/cache/apt/archives/grub-pc_2.06-2_amd64.deb
shows plenty of which's still left, as you said. But apparently one is
still not going to /dev/null for me.

Maybe you can send me a .deb with an set -x in
/var/lib/dpkg/info/grub-pc.postinst so I don't have to repackage the
whole package.