+
+#else /* HAVE_UNSETENV */
+
+# undef unsetenv
+# if !HAVE_DECL_UNSETENV
+# if VOID_UNSETENV
+extern void unsetenv (const char *);
+# else
+extern int unsetenv (const char *);
+# endif
+# endif
+
+/* Call the underlying unsetenv, in case there is hidden bookkeeping
+ that needs updating beyond just modifying environ. */
+int
+rpl_unsetenv (const char *name)
+{
+ int result = 0;
+ if (!name || !*name || strchr (name, '='))
+ {
+ errno = EINVAL;
+ return -1;
+ }
+ while (getenv (name))
+# if !VOID_UNSETENV
+ result =
+# endif
+ unsetenv (name);
+ return result;
+}
+
+#endif /* HAVE_UNSETENV */