Build function definitions for a package's builtin facets.
Compute a topological ordering of the package's transitive dependencies.
The PackageFacetConfig for the builtin depsFacet.
Build the extraDepTargets for the package and its transitive dependencies.
Also fetch pre-built releases for the package's' dependencies.
The PackageFacetConfig for the builtin dynlibFacet.
Download and unpack the package's prebuilt release archive (from GitHub).
The PackageFacetConfig for the builtin releaseFacet.
A package facet name to build function map that contains builders for
the initial set of Lake package facets (e.g., extraDep).