+#if HAVE_LIMITS_H
+# include <limits.h>
+#endif
+#ifndef CHAR_BIT
+# define CHAR_BIT 8
+#endif
+/* Upper bound on the string length of an integer converted to string.
+ 302 / 1000 is ceil (log10 (2.0)). Subtract 1 for the sign bit;
+ add 1 for integer division truncation; add 1 more for a minus sign. */
+#define INT_STRLEN_BOUND(t) ((sizeof (t) * CHAR_BIT - 1) * 302 / 1000 + 2)
+
+/* ISDIGIT differs from isdigit, as follows:
+ - Its arg may be any int or unsigned int; it need not be an unsigned char.
+ - It's guaranteed to evaluate its argument exactly once.
+ - It's typically faster.
+ Posix 1003.2-1992 section 2.5.2.1 page 50 lines 1556-1558 says that
+ only '0' through '9' are digits. Prefer ISDIGIT to isdigit unless
+ it's important to use the locale's definition of `digit' even when the
+ host does not conform to Posix. */
+#define ISDIGIT(c) ((unsigned) (c) - '0' <= 9)
+
+#if D_INO_IN_DIRENT
+# define REAL_DIR_ENTRY(dp) ((dp)->d_ino != 0)
+#else
+# define REAL_DIR_ENTRY(dp) 1
+#endif