All c++ unit tests will be written with it, and testing
should be possible out of the box.
We could make it optional, but then lots of tests will
be skipped. This creates an illusion of all tests passing
while many are simply not run. This confusion should be
avoided.
This change depends on a second commit for the windows build
in the gnucash-on-windows repository. This commit will be
pushed at the same time.
