/* Convert an ASCII hex digit to the corresponding number between 0
and 15. H should be a hexadecimal digit that satisfies isxdigit;
otherwise, the result is undefined. */
-#define XDIGIT_TO_NUM(h) ((h) < 'A' ? (h) - '0' : TOUPPER (h) - 'A' + 10)
+#define XDIGIT_TO_NUM(h) ((h) < 'A' ? (h) - '0' : c_toupper (h) - 'A' + 10)
#define X2DIGITS_TO_NUM(h1, h2) ((XDIGIT_TO_NUM (h1) << 4) + XDIGIT_TO_NUM (h2))
/* The reverse of the above: convert a number in the [0, 16) range to