https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66962
--- Comment #4 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- (In reply to Eric Niebler from comment #3) > I can't make sense of that error, or understand why you get that and I > don't. You tried the command line I gave above, with the latest concept-gcc > built from source? Yes. But it looks like you use i686-pc-cygwin and I'm running Linux.