https://issues.dlang.org/show_bug.cgi?id=22246

          Issue ID: 22246
           Summary: importC: C11 does not allow '_Alignof (expression)'
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: ibuclaw@gdcproject.org

And yet we silently accept it.

struct A { int a; };

int test()
{
    struct A a;
    return _Alignof(a);
}

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