[PATCH v2] io: Use gnulib fts implementation (BZ 22944, BZ 20331)

[Wilco Dijkstra]

Hi Adhemerval,

+  size_t val = rotr_sz ((size_t) data, 3);

Does it really make sense to add a new header reinventing the wheel rather than:

size_t val = stdc_rotate_right ((size_t) data, 3);

(there may be other cases - I noticed is_zero_or_power_of_two for example)

Cheers,
Wilco