Since Automake 1.11, the advice for setting up custom silent-rules
recipes has changed, so use the new machinery.
Also, I'm no longer mainly working on wheezy, and Automake has made the
operation field two spaces wider while I wasn't looking, so make the
output line up properly.
This means that CFD now requires Automake 1.11.2 or later to build from
the Git tree.
(cherry picked from commit
262cdcea7d345a0e523957de46fceed547f2de44)