Debug build types

[rbtcollins]

Hi, the assumption that the build type is Release when the generator isn't Visual Studio isn't portable - Debug builds in particular, but also I suspect RelWithDebInfo builds will want a debug build of cppunit (though perhaps under the same simple variable) - the multi-config generators would collapse to a single variable via the use of generator expressions -https://cmake.org/cmake/help/latest/manual/cmake-generator-expressions.7.html

[rbtcollins]

CMAKE_BUILD_TYPE can be checked to find the configured build type.