add_dune_test: Handle complex expressions in `CMAKE_GUARD`
The check if(NOT ${condition})
does not behave as expected when
condition
is a complex string expression such as A OR B
. It does
however work when condition
is a list.
Therefore convert condition
to a list by calling separate_arguments
.
Note that this change also adds missing parenthesis around condition
which also results in wrong results for complex expressions.
Closes issue #39 (closed).