digitToBasic = function digitToBasic(digit, flag) {
	//  0..25 map to ASCII a..z or A..Z
	// 26..35 map to ASCII 0..9
	return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);
}
Converts a digit/integer into a basic code point.
@see `basicToDigit()`
@private
@param {Number} digit The numeric value of a basic code point.
@returns {Number} The basic code point whose value (when used for
representing integers) is `digit`, which needs to be in the range
`0` to `base - 1`. If `flag` is non-zero, the uppercase form is
used; else, the lowercase form is used. The behavior is undefined
if `flag` is non-zero and `digit` has no uppercase form.