wc: wc -c does not optimize stdin as input by metadata

[oech3]

We have splice for pipe at input:

$ truncate -s 32GB huge
$ time cat huge| gnu58d88d243/wc -c
32000000000

real	0m2.012s
user	0m0.128s
sys	0m3.873s
$ time cat huge| wc -c
32000000000

real	0m0.388s
user	0m0.042s
sys	0m0.650s

that's fine. But uutils does not optimize stdin by metadata:

$ time wc -c <huge
32000000000

real	0m1.662s
user	0m0.040s
sys	0m1.612s
$ time gnu58d88d243/wc -c < huge
32000000000

real	0m0.004s
user	0m0.002s
sys	0m0.002s

[venoosoo]

hi i'd like to fix this

[oech3]

Just provide a PR.