Flawed logic in flag_next()

[Zaxx]

Currently, passing an "on" flag to flag_next() returns the same flag, not the next one.
If you want to iterate over "on" flags with flag_next(), you need to start with "flag+1" and not "flag", as it is mentioned in the header: "Returns the next on flag in flags, starting from (but not including) flag."

[Zaxx]

Note: the current code uses calls to the method that are in phase with the implementation of flag_next, as in the following line:

for (flag = of_next(f, FLAG_START); flag != FLAG_END; flag = of_next(f, flag + 1))

The header simply doesn't match the implementation: "Returns the next on flag in flags, starting from (but not including) flag. FLAG_END will be returned when the end of the flag set is reached. Iteration will start at the beginning of the flag set when flag is FLAG_END."

It would be more like: "Returns the next on flag in flags, starting from (and including) flag. FLAG_END will be returned when the end of the flag set is reached. Iteration will start at the beginning of the flag set when flag is FLAG_START."

[d_m]

The documentation has been changed to fit your suggestion in head.