There's a merged pull request on the void-packages repository

iperf: update to 2.1.7.
https://github.com/void-linux/void-packages/pull/36652

Description:
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#### Testing the changes
- I tested the changes in this PR: **briefly**

One patch was upstreamed. The other one was reordering includes to avoid redefinition of `struct ethhdr`; it turns out using `-D__UAPI_DEF_ETHHDR=0` has the same effect and it's easier to maintain.