fix wrong return value from wmemmove on forward copies

src/string/wmemmove.c

@@ -3,9 +3,10 @@
 
 wchar_t *wmemmove(wchar_t *d, const wchar_t *s, size_t n)
 {
+	wchar_t *d0 = d;
 	if ((size_t)(d-s) < n)
 		while (n--) d[n] = s[n];
 	else
 		while (n--) *d++ = *s++;
-	return d;
+	return d0;
 }