https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122414
--- Comment #3 from Martin Husemann <martin at netbsd dot org> --- Thanks for the documentation pointer and explanation. AFAICT full 64bit registers are saved on task switch always on a 64bit kernel (but I have to admit I have never run one on powerpc so far), so OS_MISSING_POWERPC64 should not be defined.
