use julia_version kwarg rather than ctx

Author: IanButterworth

src/Prefix.jl

@@ -669,18 +669,16 @@ function setup_dependencies(prefix::Prefix,
     deps_project = joinpath(prefix, triplet(platform), ".project")
     Pkg.activate(deps_project) do
         # Update registry first, in case the jll packages we're looking for have just been registered/updated
-        ctx = Pkg.Types.Context(;julia_version)
         outs = verbose ? stdout : devnull
         update_registry(outs)
 
-        # Add all dependencies.  Note: Pkg.add(ctx, deps) modifies in-place `deps` without
-        # notice.  We need to `deepcopy` the argument to prevent it from modying our
-        # dependencies from under our feet: <https://github.com/JuliaLang/Pkg.jl/issues/3112>.
-        Pkg_add(ctx, deepcopy(dependencies); platform=platform, io=outs)
+        # Add all dependencies.
+        Pkg_add(dependencies; platform=platform, io=outs, julia_version=julia_version)
 
         # Ony Julia v1.6, `Pkg.add()` doesn't mutate `dependencies`, so we can't use the `UUID`
         # that was found during resolution there.  Instead, we'll make use of `ctx.env` to figure
         # out the UUIDs of all our packages.
+        ctx = Pkg.Types.Context()
         dependency_uuids = Set([uuid for (uuid, pkg) in ctx.env.manifest if pkg.name ∈ dependencies_names])
 
         # Some JLLs are also standard libraries that may be present in the manifest because
@@ -718,7 +716,7 @@ function setup_dependencies(prefix::Prefix,
 
         # Re-install stdlib dependencies, but this time with `julia_version = nothing`
         if !isempty(stdlib_pkgspecs)
-            Pkg_add(ctx, stdlib_pkgspecs; io=outs, julia_version=nothing)
+            Pkg_add(stdlib_pkgspecs; io=outs, julia_version=nothing)
         end
 
         # Load their Artifacts.toml files