build failure in aarch64-opc.c on macOS

[Tom Tromey]

>>>>> "Andrew" == Andrew Pinski <pinskia@gmail.com> writes:

Andrew> On Fri, Oct 5, 2018 at 7:31 AM Tom Tromey <tom@tromey.com> wrote:
>> 
>> Hi.  A recent patch caused opcodes to fail to build on macOS (High
>> Sierra) using the version of clang I have installed (Apple's clang-902).

Andrew> This looks like a clang bug ...  {0} should have silienced the
Andrew> -Wmissing-field-initializers warning.  {0} has always been a way to
Andrew> "0" out a structure without warning.

Either way, the build used to work, and now does not.

Tom