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

musl-obstack: enable shared library
https://github.com/void-linux/void-packages/pull/22627

Description:
@pullmoll what do you think? I'm enabling it because I needed it for #22616, and I don't think there are any reasons for not building it.

That said, it could make sense now to split the package into a devel version as well, if we keep this change.