What is a good way to test that this would work with the directory layout of the packaged Julia binaries? Can such packages be created locally?

Can such packages be created locally?

Yeah, just run make install and it will create a directory in your source tree called julia-$(shorthash), which will contain the typical bin, lib, share`, etc... folders.

Not all is good. This isn't working in the package from make install.

julia> using Libdl

julia> Libdl.dlpath("libjulia")
ERROR: could not load library "libjulia"
libjulia.so: cannot open shared object file: No such file or directory
Stacktrace:
 [1] dlopen(s::String, flags::UInt32; throw_error::Bool)
   @ Base.Libc.Libdl ./libdl.jl:114
 [2] dlopen
   @ ./libdl.jl:114 [inlined]
 [3] dlpath(libname::String)
   @ Base.Libc.Libdl ./libdl.jl:237
 [4] top-level scope
   @ REPL[2]:1

I'm pretty sure this is not a problem with this PR; that happens on latest master for me as well. If you use the full SONAME (libjulia.so.1) it works.

Right, and it seems to be a difference between what make install produces and the nightly binaries. Taking that into account it passes the tests I wanted to do (building and running the embedding example and running the tests of the DynamicallyLoadedEmbedding package with the packaged Julia).

So this is ready to go from my point of view.

Apparently there is still some problem on windows https://github.com/GunnarFarneback/DynamicallyLoadedEmbedding.jl/runs/1594639460 and macos https://github.com/GunnarFarneback/DynamicallyLoadedEmbedding.jl/runs/1594639444. I should be able to get hold of a windows machine to test locally but macos is out of my reach.