I started digging more into this bug report and despite my initial misgivings, have been successful at adding sourcekit-lsp to the packaged version of Swift for Fedora 5.1.1. I have some reservations about it, however.
I found by playing with the GitHub archive URLs the swift-5.1.1-RELEASE tarballs for sourcekit-lsp, index store-db, and swift-clang-tools-extra (though they didn't show up in the tag or release pages), but what I was not able to find was a version for llvm-project (which I noted is a fork from llvm).
Without llvm-project, there are some header files missing when compiling, and when I compare against building from master via the Swift instruction page on Ubuntu,
llvm-project is definitely there along with
I opted to use a tarball that was closest to the Swift-5.1.1 release,
swift-DEVELOPMENT-SNAPSHOT-2019-10-19-a.tar.gz but that makes me uneasy because it's presumably not in total sync with the actual -RELEASE tarballs. Is there a strategy for including the llvm-project when building Swift that I'm not aware of?
I'm tracking builds of the sourcekit-lsp-included version of Swift here so as to not upset Feodra/CentOS/RHEL 8 users with all my mistakes on packaging sourcekit-lsp until I can confirm it's working.