https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61577
--- Comment #232 from John Buddery <jvb at cyberscience dot com> --- The #undef MAKE_DECL_ONE_ONLY is only for older builds, it's not needed with the gcc 11 patches. It was an alternative single line fix which works for 4.7.2 and 4.9.4, which you need to build if you're starting from scratch. This was never really the right fix, and as support for systems without MAKE_DECL_ONE_ONLY has deteriorated in later versions it became harder and harder to follow this route. I did get some intermediate versions working with a lot of hacking, but for any vaguely recent release I would recommend using the 11.1 patches instead.
