Make the call to chooseBoxingStrategy lazy again
I made it strict, as an incidental consequence of this patch: commit 5bae803a Author: Simon Peyton Jones <email@example.com> Date: Sat Sep 15 23:09:25 2012 +0100 Fix UNPACK with -fomit-interface-pragmas. But it's very important that chooseBoxingStrategy is lazy, else (in bigger programs with lots of recursion in types) GHC can loop. This showed up in Data.Sequence; and I think it was making haddock loop as well. Anyway this patch makes it lazy again.