some programs may get away without consulting GHC.Tup). Furthermore,
the renamer currently *always* asks for () to be in scope, so that
ccalls can use () as their default type; so when compiling GHC.Base we
-need (). (We could arrange suck in () only if -fglasgow-exts, but putting
-it here seems more direct.)
+need (). (We could arrange suck in () only if -XForeignFunctionInterface,
+but putting it here seems more direct.)
\begin{code}
-- | The unit datatype @()@ has one non-undefined member, the nullary