Bug#974947: dolfin: FTBFS against boost_1.74

[Drew Parsons]

Source: dolfin
Followup-For: Bug #974947

Hi Anton, what would be helpful is if the patch can be configured to
build with either boost 1.71 or boost 1.74.

Upstream won't want to necessarily depend on boost 1.74, and a common
multi-version patch will be helpful for them to manage with the
various boost versions. The patch can be pushed upstream if it does
that.

Drew