+#if defined (STDC_HEADERS) || (!defined (isascii) && !defined (HAVE_ISASCII))
+# define IN_CTYPE_DOMAIN(c) 1
+#else
+# define IN_CTYPE_DOMAIN(c) isascii(c)
+#endif
+
+#ifdef isblank
+# define ISBLANK(c) (IN_CTYPE_DOMAIN (c) && isblank (c))
+#else
+# define ISBLANK(c) ((c) == ' ' || (c) == '\t')
+#endif
+