Before this commit, all frame unwinders would be stored in the obstack of a gdbarch and accessed by using the registry system. This made for unwieldy code, and unnecessarily complex logic in the frame_unwinder implementation, along with making frame_unwind structs be unable to have non-trivial destructors. Seeing as a future patch of this series wants to refactor the frame_unwind struct to use inheritance, and we'd like to not restrict the future derived classes on what destructors are allowed. In preparation for that change, this commit changes the registry in gdbarch to instead store an std::vector, which doesn't require using an obstack and doesn't rely on a linked list. There should be no user-visible changes. Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org> Approved-By: Andrew Burgess <aburgess@redhat.com>