"Cleaner" version of D38198. The dump() functions are non-inline defined in isl-noexceptions.cpp such there is always a symbol for it that can be called in a debugger.
This gives up isl++ being header-only and requires support by the isl++ binding generator (not part of this patch).
There is an issue if PollyISL is linked as a static library. No symbol of isl-noexceptions.o is directly used, so the compiler does not add that file when linking. It seems to work with Visual Studio anyway, but not in gcc.