compatibility code for v1.0

[vtjnash]

I've written this snippet of code for inclusion in PackageCompiler.jl, but it feels like it should belong somewhere here.

let M = Module() # Prevent this from putting anything into the Main namespace
    # get a local reference to any module that may be directly referenced in the `precompile.jl` file
    for m in Base.loaded_modules_array()
        Core.isdefined(M, nameof(m)) || Core.eval(M, Expr(:const, Expr(:(=), nameof(m), m)))
    end
    for n in names(Main)
        if Core.isdefined(Main, n) && isconst(Main, n)
            m = getfield(Main, n)
            m isa Module && (Core.isdefined(M, nameof(m)) || Core.eval(M, Expr(:const, Expr(:(=), nameof(m), m))))
        end
    end
    Base.include(M, \"precompile.jl\")")
end # let

[timholy]

Where would you see it integrating?

[vtjnash]

I'm not sure—it just seemed useful to have a canonical source of this functionality, for enabling the use of precompile.jl files on v1.0.