+#ifndef GID_T_MAX
+# define GID_T_MAX TYPE_MAXIMUM (gid_t)
+#endif
+
+/* MAXUID may come from limits.h or sys/params.h. */
+#ifndef MAXUID
+# define MAXUID UID_T_MAX
+#endif
+#ifndef MAXGID
+# define MAXGID GID_T_MAX
+#endif
+
+/* Perform the equivalent of the statement `dest = strdup (src);',
+ but obtaining storage via alloca instead of from the heap. */
+
+#define V_STRDUP(dest, src) \
+ do \
+ { \
+ int _len = strlen ((src)); \
+ (dest) = (char *) alloca (_len + 1); \
+ strcpy (dest, src); \
+ } \
+ while (0)
+
+/* 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 says that only '0' through '9' are digits. Prefer ISDIGIT to
+ ISDIGIT_LOCALE 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)
+
+#ifndef strdup