https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98860
--- Comment #38 from Mikael Pettersson <mikpelinux at gmail dot com> --- After updating binutils to ba6eb62ff0ea9843a018cfd7cd06777bd66ae0a0, including the fix for BZ 27268, I was able to do a full bootstrap of current gcc head on Cygwin64. https://sourceware.org/bugzilla/show_bug.cgi?id=27268 has more detail.
