Merging the following onto the HEAD:
| 1.61.2.1 +2 -4 fptools/ghc/compiler/rename/RnHsSyn.lhs
| 1.135.2.1 +10 -0 fptools/ghc/compiler/rename/RnSource.lhs
Original comment (keithw):
Remove derivings FVs from tyClDeclFVs, because they aren't needed by
interface files. Instead, we return these FVs from
finishSourceTyClDecl.