sanitizer bug maybe.

[Jim Wilson]

On 07/10/2017 10:29 AM, George R Goffe via gcc-bugs wrote:
> ../../../../gcc/libsanitizer/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc: In function ‘int __sanitizer::TracerThread(void*)’:
> ../../../../gcc/libsanitizer/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc:276:22: error: aggregate ‘sigaltstack handler_stack’ has incomplete type and cannot be defined
>     struct sigaltstack handler_stack;

If you are doing a build using glibc mainline, then this is FSF GCC bug 
81066.
     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81066

Jim