https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101655
--- Comment #8 from cqwrteur <unlvsur at live dot com> --- He said he just adds patch for the mcf thread model. https://github.com/lhmouse/MINGW-packages-dev/blob/master/mingw-w64-gcc-git/9000-gcc-10-branch-Added-mcf-thread-model-support-from-mcfgthread.patch And he changed things in the makefile to enable -fno-ident -O3 -march=native.