After spending an afternoon on this, I think the problem is related to the fact that geos::geom::CoordinateSequenceFactory has virtual methods, and the instance is not complete, and the dynamic_cast at source:/trunk/tests/unit/geom/CoordinateArraySequenceFactoryTest.cpp@3496#L53 is not valid.
From http://www.cplusplus.com/doc/tutorial/typecasting/ in the dynamic_cast section
When dynamic_cast cannot cast a pointer because it is not a complete object of the required class -as in the second conversion in the previous example- it returns a null pointer to indicate the failure.
This test fails for me on OSX using both clang and gcc 4.2.1. That it fails on two recent compilers makes me think the problem is that the test is bad, and that it succeeded before was just luck.
