POSIX 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 int) (c) - '0' <= 9)
+# define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
/* Return true if STR represents an unsigned decimal integer. */