[make3]

OP's code is much easier to understand, though, which is the main (only) purpose of their code

[cs702]

Can't argue with that! :-)

For what it's worth, you can keep both, and make parallel vs sequential execution an option, with a boolean flag.

You can also leave the sequential code as a comment explaining what the parallel code does.

Or, if slow execution doesn't bother you, leave it as is.

[bradfitz]

You're replying to somebody who was arguing for readability being its virtue and you're proposing ... adding options and alternate code paths? :)

[cs702]

Touché. I just updated my comment :-)

[anytime5704]

Via a boolean parameter, no less.