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

WIP: clamav: update to 1.0.1.
https://github.com/void-linux/void-packages/pull/41188

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

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### Things still to do:

 - [ ] Verify that this still works as before and I didn't accidentally change any options
 - [x] Tell cmake to put stuff where it belongs (conf dir -> `/etc` and database dir -> `/var/lib/_clamav`)
 - [x] add services for at least clamav and freshclam
 - [ ] fix cross compilation
 - [ ] fix musl