https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82757
--- Comment #9 from Alan Modra <amodra at gmail dot com> --- If you start off with "___gnu_lto_", there is code in simple_object_elf.c to handle the extra '_', and now in binutils too. Skipping just one '_' will leave you with a symbol that matches "__gnu_lto_", and will trigger the gold warning. Skipping two chars will give you "_gnu_lto_" which ought to be fine. Of course on x86_64, you'll start off with "__gnu_lto_", skip two chars to give "gnu_lto_", which also ought to be fine. Even if it matches some user symbol.
