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Fix CAF_BLACKHOLE and BLACKHOLE_BQ entry code for SMP case (it was
going into a busy locking state through comparing against the wrong
info pointer)

This commit adds in the current state of our SMP support.  Notably,
this allows the new way 's' to be built, providing support for running
multiple Haskell threads simultaneously on top of any pthreads
implementation, the idea being to take advantage of commodity SMP
boxes.

Don't expect to get much of a speedup yet; due to the excessive
locking required to synchronise access to mutable heap objects, you'll
see a slowdown in most cases, even on a UP machine.  The best I've
seen is a 1.6-1.7 speedup on an example that did no locking (two
optimised nfibs in parallel).

	- new RTS -N flag specifies how many pthreads to start.

	- new driver -smp flag, tells the driver to use way 's'.

	- new compiler -fsmp option (not for user comsumption)
	  tells the compiler not to generate direct jumps to
	  thunk entry code.

	- largely rewritten scheduler

	- _ccall_GC is now done by handing back a "token" to the
	  RTS before executing the ccall; it should now be possible
	  to execute blocking ccalls in the current thread while
	  allowing the RTS to continue running Haskell threads as
	  normal.

	- you can only call thread-safe C libraries from a way 's'
	  build, of course.

Pthread support is still incomplete, and weird things (including
deadlocks) are likely to happen.

Support for thread{WaitRead,WaitWrite,Delay}.  These should behave
identically to the 3.02 implementations.

We now have the virtual timer on during all program runs, which ticks
at 50Hz by default.  This is used to implement threadDelay, so you
won't get any better granularity than the tick frequency
unfortunately.  It remains to be seen whether using the virtual timer
will have a measurable impact on performance for non-threadDelaying
programs.

All operations in the I/O subsystem should now be non-blocking with
respect to other running Haskell threads.  It remains to be seen
whether this will have a measurable performance impact on
non-concurrent programs (probably not).

Assembler/Disassembler: handle and print calls to compiled code
Evaluator: return to scheduler when entering unknown closure
StgCRun: debugging trace in miniinterpreter (temporary)
Updates: fix normal and vectored returns to Hugs

Fix ifdef INTERPRETER code fragment.

Made rts_evalIO() stricter, i.e.,

   rts_evalIO( action );

will now essentially cause `action' to be applied
to the following (imaginary) defn of `evalIO':

    evalIO :: IO a -> IO a
    evalIO action = action >>= \ x -> x `seq` return x

instead of just

    evalIO :: IO a -> IO a
    evalIO action = action >>= \ x -> return x

The old, lazier behaviour is now available via rts_evalLazyIO().

Support for "unregisterised" builds.  An unregisterised build doesn't
use the assembly mangler, doesn't do tail jumping (uses the
mini-interpreter), and doesn't use global register variables.

Plenty of cleanups and bugfixes in the process.

Add way 'u' to GhcLibWays to get unregisterised libs & RTS.

[ note: not *quite* working fully yet... there's still a bug or two
  lurking ]

(this is number 9 of 9 commits to be applied together)

  Usage verification changes / ticky-ticky changes:

  We want to verify that SingleEntry thunks are indeed entered at most
  once.  In order to do this, -ticky / -DTICKY_TICKY turns on eager
  blackholing.  We blackhole with new blackholes: SE_BLACKHOLE and
  SE_CAF_BLACKHOLE.  We will enter one of these if we attempt to enter
  a SingleEntry thunk twice.  Note that CAFs are dealt with in by
  codeGen, and ordinary thunks by the RTS.

  We also want to see how many times we enter each Updatable thunk.
  To this end, we have modified -ticky.  When -ticky is on, we update
  with a permanent indirection, and arrange that when we enter a
  permanent indirection we count the entry and then convert the
  indirection to a normal indirection.  This gives us a means of
  counting the number of thunks entered again after the first entry.
  Obviously this screws up profiling, and so you can't build a ticky
  and profiling compiler any more.

  Also a few other changes that didn't make it into the previous 8
  commits, but form a part of this set.

Misc tweaks to Win32 DLL setup

More profiling fixes.  Profiles looking more reasonable, but for best
results add the -caf-all switch to GHC.

Some fixes to profiling stuff.

Improvements to the threading model.

   - asynchronous exceptions supported.

	- killThread# can now raise an exception in the specified
	  thread.  It's new type is

		killThread# :: ThreadId# -> Exception -> IO ()

	  High-level versions:

		killThread :: ThreadId -> IO ()
		raiseInThread :: ThreadId -> Exception -> IO ()

	  (killThread raises a 'ThreadKilled' exception in the
	   specified thread).

	  If the thread has no exception handler, it is killed
	  as before.  Otherwise, the exception is passed to
	  the innermost CATCH_FRAME and the thread is woken up
	  if it was blocked.  The current computation is
	  suspended, instead of being replaced by the exception
	  (as is the case with throw).

	  Sending an exception to the current thread works too.

   - new primitive: myThreadId# :: IO ThreadId# and corresponding
     high-level version myThreadId :: IO ThreadId.

   - new primitive: yield# :: IO (), and yield :: IO ().

   - the TSO now contains a pointer to the resource currently blocked
     on (MVAR or BLACKHOLE_BQ).

  - Add a giant comment to TSO.h about what the various link fields
    are supposed to do, and invariants etc.

Remove flags field from info tables; create a separate table of flags
indexed by the closure type in the RTS.

Include CAF_ENTEREDs on the mutables list so they get scavenged correctly.

When putting the RTS in a DLL, we have to delay filling in the
Charlike and Intlike tables until load-time.

- s/finalise/finalize/g
- make finalize run the finalizer immediately, and wait for its completion
- make mkWeak take a (Maybe (IO ())) for the finalizer argument
- remove mkWeakNoFinalizer

Copyright police.

Remove MUT_ARR_WORDS.  I'm not sure why we had it in the first place.

- Add ticky counter for total bytes copied during GC.
- Separate mutable list into two lists, a "mut once" list for
  old generation indirections and MUT_CONS cells, and a "mut many"
  list for mutable arrays, TSOs etc.  Objects on the "mut once" list
  will be eagerly promoted.

- Add finalise#
- Add mkWeakNoFinaliser
- Move deRefWeak# from an out-of-line primop to an inline one.

Finally!  This commits the ongoing saga of Simon's hygiene sweep

FUNCTIONALITY
~~~~~~~~~~~~~
a) The 'unused variable' warnings from the renamer work.  
b) Better error messages here and there, esp type checker
c) Fixities for Haskell 98 (maybe I'd done that before)
d) Lazy reporting of name clashes for Haskell 98 (ditto)

HYGIENE
~~~~~~~
a) type OccName has its own module.  OccNames are represented
   by a single FastString, not three as in the last round.  This
   string is held in Z-encoded form; a decoding function decodes
   for printing in user error messages.  There's a nice tight
   encoding for (,,,,,,,,,,,,,,,,,,,,,,,,,,,,,)

b) type Module is a proper ADT, in module OccName

c) type RdrName is a proper ADT, in its own module

d) type Name has a new, somwhat tidier, representation

e) much grunting in the renamer to get Provenances right.
   This makes error messages look better (no spurious qualifiers)

- Add Stable Names

- Stable pointers and stable names are now both provided by the
  "Stable" module in ghc/lib/exts.  Documentation is updated, and Foriegn
  still exports the stable pointer operations for backwards compatibility.

Resurrect ticky-ticky profiling.  Not quite polished yet, but it
compiles and produces some reasonable-looking stats.

- BLACKHOLE_BQ is a mutable object, because new threads get added to
  its blocking_queue field.  Hence add a mut_link field and treat it
  as mutable in the garbage collector.

- Change StgBlackHole to StgBlockingQueue while I'm at it.

- Optimise evacuation of black holes: don't copy the padding
  words, just skip over them.

- Several garbage collection fixes.

- Improve sanity checking: now the older generations are fully checked
  at each GC.

- Add new object BLACKHOLE_BQ: now a BLACKHOLE is defined as having an
  empty blocking queue, and the first time a thread blocks on a BLACKHOLE
  it is changed into a BLACKHOLE_BQ.

- Remove UPD_INPLACE1 and replace it with UPD_IND in the two places it
  was used.  UPD_INPLACE1 wouldn't have worked in a generational setting.

Remove 'const' modifier from static closure declarations.  Static
closures are meant to live in R/W data space.

Added a generational garbage collector.

The collector is reliable but fairly untuned as yet.  It works with an
arbitrary number of generations: use +RTS -G<gens> to change the
number of generations used (default 2).

Stats: +RTS -Sstderr is quite useful, but to really see what's going
on compile the RTS with -DDEBUG and use +RTS -D32.

ARR_PTRS removed - it wasn't used anywhere.

Sanity checking improved:
	- free blocks are now spammed when sanity checking is turned on
	- a check for leaking blocks is performed after each GC.

Move 4.01 onto the main trunk.