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

occt: update to 7.4.0.
https://github.com/void-linux/void-packages/pull/15102

Description:
Tracking PR.

- [x] actually build the hole thing locally for all relevant archs
- [x] ~check what freecad says about it~ requires rebuild
- [ ] test the musl patches (anyone?)
- [x] include env scripts mentioned by @karl-nilsson [here](https://github.com/void-linux/void-packages/pull/15102#issuecomment-538666759)

@karl-nilsson @yopito