@Jonathan-Rizzo
I figured this out myself, so hopefully it's all correct. But it works
Make sure your shell is in the source directory
Run: "./scripts/feeds install <<your lib>>"
Often this works. If it doesn't we will install manually.
mkdir -p package/libs/<<your lib>>
cd package/libs/<<your lib>>
wget https://raw.githubusercontent.com/openwrt/packages/master/libs/<<your lib>>/Makefile
cd ../../../
make package/libs/<<your-lib>>/compile
make package/libs/<<your-lib>>/install
make package/libs/<<your-lib>>/clean
More information here:
https://openwrt.org/docs/guide-developer/build-system/start
Secondly, this may be a cleaner way to do it, but I haven't tried:
https://navneetstudynotes.blogspot.com/2015/04/building-new-package-with-openwrt.html