Tidied up the handling of the code that emits the precedence level
predicates that gets used in applications of showParen and readParen.

Two new Dark Corner regression tests:

- testing the derived Show&Read instances for constructors with
  a field label that is a varsym rather than a varid.
- check that the default fixity & assoc of an operator is 'infixl 9'.

New option, -fail, to indicate failure (whatever the return code).

Make sure that instance gates have their home modules
loaded by RnIfaces.getImportedInstDecls.  This was causing
Kevin Atkinson's missing-instance bug.

* If a field label is a 'varsym', wrap parens around it when
  Show'ing and Read'ing it back in.

* If there's no fixity decl for a 'consym', the default is
  for it to be left-assoc.

Don't use WinSock under cygwin

Don't compile in WinSock support under cygwin

exitWith: don't call exit(), but use the RTS' shutdownHaskellAndExit()

New RTS entry point, shutdownHaskellAndExit(), which does what the name
implies - used when you want to exit from within Haskell code (e.g.,
System.exitWith.)

Remove final fflush() - it seems to be incompatible with recent
releases of Linux's libc implementation, and we don't use stdio in any
case.

The allocator for mega groups now checks if consecutive megablocks on
the free list are contiguous in memory. The omission of this check
caused all kinds of funny runtime errors and took away at least five
happy years of my life...  :-{

8-bit clarity

Make this more Haskell 1.3-insensitive

Allow the following (not strictly H98) construct:

    do
	blah
	e $ do
	blah

This doesn't break any existing code, just allows more programs
through.  Only the semantics for layout after a 'do' have changed.

Add a test for deriving Show (f (f a)); makes Hugs hang

Make the r.u.n message happen only with -DDEBUG

Back out a change that creeped in by mistake.

Clean out objects generated from assembly files.

Made the compilation of the RTS almost warning-free and improved the
output of some "barf"s in the garbage collector . This is part of my
epic crusade against "scavenge_mut_list: strange object?"... :-(

Suppress warnings by making some static symbols extern.  Sigh.

Someone with a big stick told me to remove -ddump-cpranalyse
Use -ddump-cpranal instead.

CPR Analysis Mark 2. Slightly more elegant,  and (I believe) now
copes correctly with references to CAFS and non-top level function
bindings.

(keving)

Add dump-cpranal to agree with the users_guide.  dump-cpranalyse will
still work but is deprecated and could be removed by someone with
a bigger stick than me.

Back out changes for "specialid"s.  It didn't work this way: there was
a conflict in the grammar.

Add explanatory comments

Fix SetLevels so that it does not clone top-level bindings, but it
*does* clone bindings that are destined for the top level.

The global invariant is that the top level bindings are always
unique, and never cloned.

Some renamer fixes

* Correct the defn of Rename.isOrphanRule (caused a Sergey bug)

* Tidy up the Rename.implicitFVs stuff

Propagate changes for tcSimplifyToDicts

Reduce renamer warnings

* Add Type.repType

* Re-express splitRepTyConApp_maybe using repType

* Use the new repType in Core2Stg

	The bug was that we ended up with a binding like
		let x = /\a -> 3# +# y
		in ...
	and this should turn into an STG case, but the big lambda
	fooled the core-to-STG pass

Improve common sub-expression stuff
	- better hash function
	- add Const.isBoxedDataCon, and use it in CSE
	- don't CSE for nullary constructors

Fix lost specialisations.  There were two problems

	{-# SPECIALISE f :: Int -> Rational #-}
	fromIntegral	=  fromInteger . toInteger

This generates

	fromIntegral_spec = fromIntegral d

for some suitable dictionary d.  But since fromIntegral is small,
it got inlined into fromIntegral_spec, thus losing the specialised
call (fromIntegral d) that was the whole raison d'etre of fromIntegral_spec.
Haskish solution: add an inlne pragma for the _spec things:

	fromIntegral_spec = _inline_me (fromIntegral d)

Now we won't inline inside.  But this showed up a related problem.  The
typechecker tries to common up overloaded things, so it actually generates

	m = fromIntegral d
	fromIntegral_spec = _inline_me m

which is pretty stupid.  Using tcSimplifyToDicts (instead of tcSimplify)
in TcBinds.tcSpecSigs fixes this.

a couple more weird cases for lexing of qualified names.

Fix some pretty subtle bugs in the lexing of qualified names.

writeHandle has been removed.

Move -fwarn-unused-{binds,matches} back into -W (two votes for, one
against).

nit-picking lexical tests for M.<reservedid> and M.<specialid>

Jump to the join point when returning a new constructor to a bind
default.  Fixes:  recent panic in mkStaticAlgReturnCode.

Don't treat GHC extension keywords as such when recognising qualified
varids.  This is a quick fix for the bug that M.label isn't recognised
as a qvarid with -fglasgow-exts on.

Don't attempt to close stdin or stdout.  From Kevin Atkinson
<kevinatk@home.com>.