https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117630
--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> --- There is a patch under review for GCC 15 which should make the unstable ABI configuration only support SSO string, eventually (the current patch doesn't do it, but I would follow up on it). Building the unstable ABI configuration would also remove the static destructors in compatibility-c++0x.cc which exist for backwards compatibility with the gcc-4 ABI.
