[Patch, libstdc++/65420] Use constexpr variables as regex_constans flags

[Jonathan Wakely]

On 15/03/15 23:27 -0700, Tim Shen wrote:
>+#include <regex>
>+#include <testsuite_hooks.h>
>+
>+// libstdc++/65420
>+void
>+test01()
>+{
>+  bool test __attribute__((unused)) = true;

I forgot to say that for a { dg-do compile } test you don't need a
'test' variable and don't need to #include <testsuite_hooks.h>,