http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55431
--- Comment #7 from Alan Modra <amodra at gmail dot com> 2013-02-12 13:23:59 UTC --- On thinking about this a little more, the idea of using /proc/self/auxv isn't that good. MD_FALLBACK_FRAME_STATE_FOR is only needed for older kernels; Kernels 2.6.15 and later provide a vdso with unwind info for signal frames. So I don't think it makes sense to restrict libgcc's support for old kernels to 2.6.0 thru 2.6.14. If we're going to support old kernels, then we ought to continue supporting them all as best we can. And, yes, really old kernels used a different sigcontext for the simple reason that they predated altivec. I'm inclined to close this bug as WONTFIX, or possibly make __libc_stack_end weak so that libgcc builds with musl libc.