Update copyright years.

From-SVN: r219188
diff --git a/libcpp/charset.c b/libcpp/charset.c
index a34dafb..b427638 100644
--- a/libcpp/charset.c
+++ b/libcpp/charset.c
@@ -1,5 +1,5 @@
 /* CPP Library - charsets
-   Copyright (C) 1998-2014 Free Software Foundation, Inc.
+   Copyright (C) 1998-2015 Free Software Foundation, Inc.
 
    Broken out of c-lex.c Apr 2003, adding valid C99 UCN ranges.