Description:
------------
I think that in the function 'mbfl_identify_encoding2' (in ext/mbstring/libmbfl/mbfl/mbfilter.c), the variable 'bad' was instantiated in a wrong place.

The same is in 'mbfl_encoding_detector_feed' and 'mbfl_identify_encoding'

Test script:
---------------
	if (p != NULL) {
		bad = 0;
		while (n > 0) {
			for (i = 0; i < num; i++) {
				[...]
			}
			if ((num - 1) <= bad && !strict) {
				break;
			}
			p++;
			n--;
		}
	}

I think that 'bad' variable must be inner the while cycle, otherwise the if control on bad number detect is very poor.