- import list tweaks
- moved the code that decides that a StgCon really shouldn't
  be mapped to a static constructor but an updateable thunk
  if it contains lit-lits from the codegen into the CoreToStg
  translation.

  Added an extra case to this code to deal with StgCon's that contain
  references to values that reside in a DLL, where we also have to
  opt for an updateable thunk instead of a static constructor. Only
  applies when compiling on/for Win32 platforms.