Bug#865671: scotch hides build failures

[Helmut Grohne]

Source: scotch
Version: 5.1.12b.dfsg-2
Severity: serious
Justification: policy 4.6
Tags: jessie stretch buster sid
User: helmutg at debian.org
Usertags: rebootstrap

When some part of scotch's build fails (e.g. mpicc), the build continues
and may produce a broken package. This violates Debian Policy section
4.6. The cause is the use of an embedded makefile script without the
recommended "set -e".

Helmut