https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97618
--- Comment #1 from Brecht Sanders <brechtsanders at users dot sourceforge.net> --- I see a similar issue when building mpfr with the resulting compiler, but here the error is: build_mingw\i686-w64-mingw32\libgcc/../../../libgcc/config/libbid/bid128_div.c:616: undefined reference to `LC4' and replacing -O3 with -O2 or -Os didn't work.