[cvs-nhc98] patch applied (hat): Correct bugs introduced by previous bug-fixes.

[Malcolm Wallace]

Tue Apr 29 08:26:59 PDT 2003  olaf
  * Correct bugs introduced by previous bug-fixes.
  
  Malcolm Wallace reported that the hat-transformed prelude would no longer compile. There were two sorts of errors:
  
  Hat/PreludeBuiltin.hs:1:
      Type constructor or class not in scope: `Char'
  
  This was because import of the sort "TraceOrigPrelude" had been dropped by some inappropriate filtering of such imports. Now they are back again.
  
  
  Hat/PreludeBuiltin.hs:108: Variable not in scope: `Prelude.sempty'
  
  Calls in instances needed qualification when the class was imported qualified. However, the implementation always qualified the ids; when the class did not have a qualfifier it used Prelude. Now no qualfication happens in such a case.

    M ./src/hattrans/AuxFile.hs -6 +8
    M ./src/hattrans/TraceTrans.hs -1 +3