-/* Bound on length of the string representing an integer value of type T.
- Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
+/* Return zero if T can be determined to be an unsigned type.
+ Otherwise, return 1.
+ When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a
+ tighter bound. Otherwise, it overestimates the true bound by one byte
+ when applied to unsigned types of size 2, 4, 16, ... bytes.
+ The symbol signed_type_or_expr__ is private to this header file. */
+#if __GNUC__ >= 2
+# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))
+#else
+# define signed_type_or_expr__(t) 1
+#endif
+
+/* Bound on length of the string representing an integer type or expression T.
+ Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485;