[Bug go/81893] New: [8 regression] compilation error in libgo starting with r251127

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81893

            Bug ID: 81893
           Summary: [8 regression] compilation error in libgo starting
                    with r251127
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: go
          Assignee: ian at airs dot com
          Reporter: seurer at gcc dot gnu.org
                CC: cmang at google dot com
  Target Milestone: ---

I only saw this on powerpc64 big endian.

/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c: In function 'dumpregs':
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:349:19: error:
initialization of 'mcontext_t * {aka struct <anonymous> *}' from incompatible
pointer type 'union uc_regs_ptr *' [-Werror=incompatible-pointer-types]
   mcontext_t *m = &((ucontext_t*)(context))->uc_mcontext;
                   ^
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:353:37: error: 'mcontext_t
{aka struct <anonymous>}' has no member named 'regs'; did you mean 'gregs'?
    runtime_printf("r%d %X\n", i, m->regs->gpr[i]);
                                     ^~~~
                                     gregs
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:354:33: error: 'mcontext_t
{aka struct <anonymous>}' has no member named 'regs'; did you mean 'gregs'?
   runtime_printf("pc  %X\n", m->regs->nip);
                                 ^~~~
                                 gregs
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:355:33: error: 'mcontext_t
{aka struct <anonymous>}' has no member named 'regs'; did you mean 'gregs'?
   runtime_printf("msr %X\n", m->regs->msr);
                                 ^~~~
                                 gregs
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:356:33: error: 'mcontext_t
{aka struct <anonymous>}' has no member named 'regs'; did you mean 'gregs'?
   runtime_printf("cr  %X\n", m->regs->ccr);
                                 ^~~~
                                 gregs
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:357:33: error: 'mcontext_t
{aka struct <anonymous>}' has no member named 'regs'; did you mean 'gregs'?
   runtime_printf("lr  %X\n", m->regs->link);
                                 ^~~~
                                 gregs
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:358:33: error: 'mcontext_t
{aka struct <anonymous>}' has no member named 'regs'; did you mean 'gregs'?
   runtime_printf("ctr %X\n", m->regs->ctr);
                                 ^~~~
                                 gregs
/home/seurer/gcc/gcc-trunk/libgo/runtime/go-signal.c:359:33: error: 'mcontext_t
{aka struct <anonymous>}' has no member named 'regs'; did you mean 'gregs'?
   runtime_printf("xer %X\n", m->regs->xer);
                                 ^~~~
                                 gregs