audio/HVSC-Update: Fix build with Clang 6
The configure check for ios::binary fails with
/usr/include/stdlib.h:97:1: error: function declared 'noreturn' after its first declaration
_Noreturn void exit(int);
^
/usr/include/sys/cdefs.h:280:22: note: expanded from macro '_Noreturn'
#define _Noreturn noreturn
^
conftest.cc:9:6: note: declaration missing 'noreturn' attribute is here
void exit (int);
^
which leads to the build falling back to using ios::bin due to
having HAVE_IOS_BIN defined.