[Bug sanitizer/78294] -fsanitize=thread broken

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78294

--- Comment #10 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
It might make sense to add -fuse-ld=bfd to the AM_CXXFLAGS for now.
(lld is also broken.)