wc: fix arguments not overriding

[Yykz]

Made wc arguments override to match GNU wc behavior.

current uutils/coreutils:

$ echo "foo"|./coreutils wc -ll -l
error: the argument '--lines' cannot be used multiple times

$ echo "foo"|./coreutils wc --total=always --total=never
error: the argument '--total <WHEN>' cannot be used multiple times

GNU:

$ echo "foo"|wc -ll -l
1

$ echo "foo"|wc --total=always --total=never
      1       1       4

[sylvestre]

Looks good but could you please add a test to make sure we don't regress ?

[Yykz]

Looks good but could you please add a test to make sure we don't regress ?

Sure

[sylvestre]

thanks