[Dune] Set environment variables for dunecontrol

[Christoph Grüninger]

Hi Dune,
I am wondering what's the best way to set environment variables for
dunecontrol. For example I need to set MPICC for MPI or CC and CXX 
to use clang. In both cases I place these variables before the 
command invoking dunecontrol. But it's cumbersome and error-prone.
I'd like to add to my opts file, but simply adding the variable and
its value does not seem to work.

Do I miss something? What are you doing?

Have a nice weekend
Christoph

-- 
[..] we shall send to the moon, 240,000 miles away from the control
station in Houston, a giant rocket [..] and then return it safely to
earth, re-entering the atmosphere at speeds of over 25,000 miles per
hour, causing heat about half that of the temperature of the sun,
almost as hot as it is here today, [..] then we must be bold.
[John F. Kennedy Moon Speech - September 12, 1962 - Rice Stadium]