__va_copy
#define __va_copy(dest, src) ((void)((dest) = (src)))
#define __va_copy(dest, src) \
#define __va_copy(to, from) __va_void(((to) = (from)))
#define __va_copy(to, from) __va_void(((to)[0] = (from)[0]))
#define __va_copy(to, from) __va_void(((to) = (from)))
#define __va_copy(to, from) __builtin_va_copy(to, from)