This is an interesting question for my use of Lua.
I’ve built a scripting front end for a purchased, non-GPL, Ethernet/IP stack. The stack cannot be freely distributed in source form by its license.
So long as the lib is only used within my company there is not an issue.
Sharing could be done with the GPL portion of the library with a text file informing the would be user where to get the key part that makes it worthwhile. Would anyone really be interested in such a crippled part of a library?