+#ifndef va_copy
+/*
+ * Since an obvious implementation of va_list would be to make it a
+ * pointer into the stack frame, a simple assignment will work on
+ * many systems. But let's try to be more portable.
+ */
+#ifdef __va_copy
+#define va_copy(dst, src) __va_copy(dst, src)
+#else
+#define va_copy(dst, src) ((dst) = (src))
+#endif
+#endif
+