...I hope this works. ...at some point we need a clear program logic
for this. Right now it is a nightmare. There are too many different
implicit cases one has to consider.

# Conflicts:
#   cmake/Files_and_Targets.txt

introduce ifdefs for chase

See merge request fleur/fleur!12

...This is to save the climate. :)

...I remembered that it produced compiler-dependent results.

This is done to make the determination of energy parameters more robust.
It seems to break some tests. But this does not necessarily mean that it
is wrong.