(c) >= '0' && (c) <= '9' ? (c) - '0' + 52 : \
(c) == '+' ? 62 : 63 )
-static const char *base64_chars =
+static const char *const base64_chars =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static void read_utf7(charset_spec const *charset, long int input_chr,