__va_void
#define __va_copy(to, from) __va_void(((to) = (from)))
#define __va_copy(to, from) __va_void(((to)[0] = (from)[0]))
#define __va_end(list) __va_void(0)
__va_void(((list) = (__va_list)&__builtin_va_alist))
#define __va_copy(to, from) __va_void(((to) = (from)))
#define __va_end(list) __va_void(0)