The $lib output refers to the terminfo database in $out, which is about
10x larger than the ncurses shared library. Splitting these outputs
saves a small amount of space for any derivations that use the terminfo
database but not the ncurses library, but we do not have evidence that
any such exist.
The name of the GHC derivation must match the name and version tuple GHC
uses to identify itself, because the withPackages wrapper uses that name
to construct installation library paths etc., and those paths must match
those constructed by the compiler. If we add another tag to the name
that GHC itself doesn't use, then the paths assumed to exist by the
wrapper are wrong.
