Problems with head

[Simon Peyton-Jones]

| 1. Current version dies in the simplifier:
|=20
| ../../../ghc/compiler/ghc-inplace -ldl -cpp -fglasgow-exts -O=20
| -Rghc-timing  -package-name std -split-objs  -monly-3-regs =20
| -c PrelWord.lhs -o PrelWord.o
| ghc-5.01: panic! (the `impossible' happened, GHC version 5.01):
|         stack overflow

Fixed.

| 2. Yesterday's version, after Simon's GC changes, compiles but doesn't
| bootstrap: genprimopcode tries to enter absent argument.

I havn't got to this yet.  Maybe the demand analyser is wrongly claiming
that something is absent.

Simon