FlexUnit from both FlashBuilder and FlexMojos for library projects

FlashBuilder leaves its FlexUnitTestRunnerUI files in "src".
For packaging:swf FlexMojos projects, that's fine (*1), it builds them.
*1: OK, it may not be all that fine but it doesn't cause failure.
For packaging:swc FlexMojos projects, they fail with "Type was not found" etc errors! How to fix, after the break...