Update copyright years.

From-SVN: r256169
diff --git a/libgcc/udivmodsi4.c b/libgcc/udivmodsi4.c
index 5aa5eb9..69e0349 100644
--- a/libgcc/udivmodsi4.c
+++ b/libgcc/udivmodsi4.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000-2017 Free Software Foundation, Inc.
+/* Copyright (C) 2000-2018 Free Software Foundation, Inc.
 
 This file is part of GCC.