New comment by mvf on void-packages repository

https://github.com/void-linux/void-packages/pull/25526#issuecomment-769766192

Comment:
The `ui_` headers are generated, but the code that includes them doesn't depend on them, so sometimes they're not generated in time. That's also why retrying incrementally works. Unless we can fix the deps in `CMakeLists.txt`, the usual workaround is `disable_parallel_build=yes`.