Increment variable for argument parsing.
Increment variable for argument parsing.

Without this, there is an off-by-one error when the target is calculated
whenever the `-experimental-io-features` flag is given.

Bug was not visible in any releases.

root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,karies/root,karies/root,olifre/root,root-mirror/root,karies/root,olifre/root,olifre/root,karies/root,olifre/root,root-mirror/root,karies/root,olifre/root,olifre/root,karies/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,karies/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,root-mirror/root,karies/root,karies/root,olifre/root