This patch sligtly re-adjusts the way in which the syntax of types 
is handled:

 * In the lexer, '.' and '*' are always accepted in types
   (previously it was conditional).  This things can't mean
   anything else in H98, which is the only reason for doing things
   conditionally in the lexer.

 * As a result '.' in types is never treated as an operator.
   Instead, lacking a 'forall' keyword, it turns into a plain parse error.

 * Test for -XKindSignatures in the renamer when processing
     a) type variable bindings
     b) types with sigs (ty :: kind-sig)

 * Make -XKindSignatures be implied by -XTypeFamilies 
   Previously this was buried in the conditonal lexing of '*'

With the
    On x86, use thread-local storage instead of stealing a reg for gct
patch, on Windows and OS X:
    error: thread-local storage not supported for this target

One of these things is not like the others:

stdPattern :: [LRep] -> Maybe StgHalfWord
stdPattern reps
  = case reps of
        []  -> Just ARG_NONE    -- just void args, probably
        [N] -> Just ARG_N
        [P] -> Just ARG_N
        [F] -> Just ARG_F
        [D] -> Just ARG_D
        [L] -> Just ARG_L

Today's debugging session was brought to you by the letter P.

- Block concat and branch-chain elimination were allowing a function call
  to return to the caller's entry point. But that doesn't leave anywhere
  for the infotable on the stack, since the SP on return must be the same
  as the SP on entry to the procedure.

 - Previously, the node was taken as a parameter, then ignored,
   for static closures. Goofy. Now, the vestigial node parameters
   are gone.

Code simplifications due to call/return separation; some improvements to how node argument is managed

Benchmarks show that using TLS instead of stealing a register is
better by a few percent on x86, due to the lack of registers.

This only affects -threaded; without -threaded we're (now) using
static storage for the GC data.

unbreaks ghc-pkg check in an installed GHC

This patch is the result of a long series of nofib-based experiments
to improve GHC's inlining heuristics.

In the end, I'm not sure how worthwhile it all was: I only got a 
   1% decrease in code size
   1% decrease in allocation
and I don't trust the runtime statistics enough to quote.

Still, in doing all this I tidied up the code quite a bit, and 
I understand it much better now, so I'm going to commit it.

The main changes are in CoreUnfold, which has lots of new comments.
Other changes:

  - litSize moves from Literal to CoreUnfold
  - interestingArg moves from SimplUtils to CoreUnfold
  - the default unfolding threshold (in StaticFlags) 
      reduces from 8 to 6 (since the size calculation 
      has changed a bit)

If worker/wrapper decides not to w/w something on the grounds that
it's too small, it should add an INLINE pragma.  Otherwise, later
in the day that small thing might now be big, and we'd wish we'd
done the w/w after all.  This only made a difference in one nofib 
program (bspt), but it's an easy change.

See Note [Don't w/w inline things (a) and (b)]

I found a couple of shortcomings in arity computation, and did
quite a bit of refactoring as a result.  Regrettably, I have
forgotten the details, but I do remember that one part was to
do with the infamous "state hack".  If we're going to use the
state-hack at all, we'd better do it right.

Anyway I think this is an improvement. The comments are more
up to date too, and more voluminous.

See Note [Case MFEs]; don't float case expressions from 
a strict context.

This patch fixes a rather obscure bug, whereby it's possible
for (case C a b of <alts>) to have altenatives that do not inclue
(C a b)!  See Note [Unreachable code] in CoreUtils.

I'm changing the details of SimplUtils.interstingArg, and don't want to
mess  up the way Specialise works, so this patch makes a specilialised
(ha) function, Specialise.interestingDict, that is used locally.

Make idDetails and idInfo into proper functions, rather than record
fields, so that we can report more informatively if you use thenm on
a non-Id.

In the case binder-swap operation (which is done in OccurAnal),
we deliberately use shadowing. But the new shadowing binder should
not inherit any fancy INLINE or NOINLINE pragmas from its parent.

This patch changes the compilation pipeline flags so that constants
are floated to the top level even in the first full laziness pass.
For some reason this was not done before.  Fixing this makes a big
improvement in 'spectral/rewrite', and has zero effect on any other
nofib benchmark.

 1. it was out of date in various ways
 2. this is not the place people look for installation instructions
 3. we have installation instructions elsewhere (e.g. the INSTALL
    file in a binary distribution)
 4. the section "layout of installed files" is now on the wiki under
    Building/Installing.

   This fixes the out of memory errors we were getting on sparc
   after the following patch:

     Fri Mar 13 03:45:16 PDT 2009  Simon Marlow <marlowsd@gmail.com>
     * Instead of a separate context-switch flag, set HpLim to zero
     Ignore-this: 6c5bbe1ce2c5ef551efe98f288483b0
     This reduces the latency between a context-switch being triggered and
     the thread returning to the scheduler, which in turn should reduce the
     cost of the GC barrier when there are many cores. 

We now use `ctypedoc` instead of `ctype` for type synonyms. `ctypedoc` was
previously only used for top-level type signatures. This change means that type
synonyms now can contain comments, just like top-level type signatures.
  
Note:
  
* I've modified `ctypedoc` so it allows implicit parameters and equational
constraints, just like ctype.
  
* Since `ctypedoc` allows nested foralls, we now allow that in type synonyms.
  
* I have inlined some productions into gentypedoc so that there is now a
non-doc version of every production with a 'doc' suffix. (Stylistic change
only, which should make the code easier to follow).
  
* It would have been nice to simplify the grammar by unifying `ctype` and 
ctypedoc` into one production, allowing comments on types everywhere (and
rejecting them after parsing, where necessary).  This is however not possible
since it leads to ambiguity. The reason is the support for comments on record
fields:
  
> data R = R { field :: Int -- ^ comment on the field }
  
If we allow comments on types here, it's not clear if the comment applies
to 'field' or to 'Int'. So we must use `ctype` to describe the type.

This avoids some showSDoc's where the String then gets converted back
into an SDoc.