* lv2lint: fix build and switch to elfutils
1. The homepage and source had rotted. Update to the new ones, and use `fetchFromSourcehut`.
2. The package didn't (and to the best of my trying, won't) build on Darwin, so mark it as `platforms = platforms.linux;`
3. The appropriate Meson flags for turning on the possible lint tests weren't set. Set them and enable the features if possible.
4. Switch from using unmaintained `libelf` to `elfutils`.
