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Update the FFI docs to use hs_init()/hs_exit() rather than
startupHaskell()/shutdownHaskell().

Flesh out support for hs_init() and hs_exit() according to the latest
FFI spec.

For GHC, I also added:

  hs_add_root( void (*fn)(void) );

which is used to specify the root module.  This *must* be called prior
to invoking any Haskell functions.

The previous way of doing things still works:

  startupHaskell( argc, argv, root );

but the right way to do this is now

  hs_init( &argc, &argv );
  hs_add_root( root );

It is possible to invoke hs_add_root() multiple times with different
roots.

- setProgArgv() has been removed; it was unused and looks like it was
  there to support STG Hugs.

Initialise prog_argc, prog_argv and rts_argc to sensible zero values
just in case hs_init() is called without passing any arguments in.

- Add headers
- Make initThreadLabels multi-init-safe

Add #ifdef around an assertion that only holds for the threaded RTS.

Fixes to make previous revision compatible with autoconf 2.13.

Un-break the non-threaded RTS
Sorry :-/

Synched OpenGL detection macro with HOpenGL-1.04.
TODO: Modularization of the macro and caching.

This commit fixes many bugs and limitations in the threaded RTS.
There are still some issues remaining, though.

The following bugs should have been fixed:

- [+] "safe" calls could cause crashes
- [+] yieldToReturningWorker/grabReturnCapability
    -     It used to deadlock.
- [+] couldn't wake blocked workers
    -     Calls into the RTS could go unanswered for a long time, and
          that includes ordinary callbacks in some circumstances.
- [+] couldn't block on an MVar and expect to be woken up by a signal
      handler
    -     Depending on the exact situation, the RTS shut down or
          blocked forever and ignored the signal.
- [+] The locking scheme in RtsAPI.c didn't work
- [+] run_thread label in wrong place (schedule())
- [+] Deadlock in GHC.Handle
    -     if a signal arrived at the wrong time, an mvar was never
          filled again
- [+] Signals delivered to the "wrong" thread were ignored or handled
      too late.

Issues:
*) If GC can move TSO objects (I don't know - can it?), then ghci
will occasionally crash when calling foreign functions, because the
parameters are stored on the TSO stack.

*) There is still a race condition lurking in the code
(both threaded and non-threaded RTS are affected):
If a signal arrives after the check for pending signals in
schedule(), but before the call to select() in awaitEvent(),
select() will be called anyway. The signal handler will be
executed much later than expected.

*) For Win32, GHC doesn't yet support non-blocking IO, so while a
thread is waiting for IO, no call-ins can happen. If the RTS is
blocked in awaitEvent, it uses a polling loop on Win32, so call-ins
should work (although the polling loop looks ugly).

*) Deadlock detection is disabled for the threaded rts, because I
don't know how to do it properly in the presence of foreign call-ins
from foreign threads.
This causes the tests conc031, conc033 and conc034 to fail.

*) "safe" is currently treated as "threadsafe". Implementing "safe" in
a way that blocks other Haskell threads is more difficult than was
thought at first. I think it could be done with a few additional lines
of code, but personally, I'm strongly in favour of abolishing the
distinction.

*) Running finalizers at program termination is inefficient - there
are two OS threads passing messages back and forth for every finalizer
that is run. Also (just as in the non-threaded case) the finalizers
are run in parallel to any remaining haskell threads and to any
foreign call-ins that might still happen.

remove setting of $(way_) and $(_way); these are now set in boilerplate.mk

- Generalise seq to allow an unlifted type in its second argument.  This
  works because seq is *always* inlined and replaced by a case.

- Remove getTag, a wired-in Id with an unfolding, with a definition
  in GHC.Base:

	getTag x = x `seq` dataToTag# x

  this is why we required the above generalisation to seq (dataToTag#
  returns an Int#).  See the comments in GHC.Base for more details.

- As a side-effect, this fixes a bug in the interpreter, where the
  compiler optimised away the evaluation of the argument to dataToTag#,
  but the interpreter ended up passing it an unevaluated thunk (nullary
  constructors aren't always evaluated in GHCi, but the simplifier
  assumes they are).  Now, in the interpreter, getTag won't be inlined
  so the compiler can't optimise away the evaluation, and we're saved.

  The real bug here is either (a) dataToTag# requires an evaluated
  argument or (b) the interpreter doesn't supply it with one, take your
  pick.

- Reverse the code for workers and wrappers for nullary constructors.
  For some reason it was the wrong way around, but the effects were
  harmless since they both evaluate to the same thing.

- When passing a nullary constructor as an argument, we should pass
  the name of the worker rather than the wrapper.  Again, this is
  mostly harmless, but it enables some small simplification in
  pushAtom.

- Rearrange/cleanup pushAtom.

Perform 'tidying' on the implicit bindings before emitting
	External Core.  We were getting silly bindings like
		\ tpl -> case tpl of tpl -> (tpl,tpl) -> tpl

	Maybe we should add these implicit bindings in CoreTidy,
	rather than in both MkExternalCore and CorePrep?

Fix compilation with DEBUG

We have to desugar polymorphic FFI declarations properly, too.
(companion commit to rev. 1.84 of TcType.lhs).

Allow FFI declarations to have polymorphic types. eg:

foreign import ccall unsafe "stdlib.h &free" pFree :: FunPtr (Ptr a -> IO ())

(the change actually removed a line, the extra lines are because I
reformatted an import declaration).

Refine documentation of newtype-deriving stuff

Document warning suppression with leading underscore on variable names

Suppress "No explicit method or default decl given for m"
	if the method name starts with an underscore

	This in response to a suggestion by George Russel

Improve error message again

Fix two small bugs in deriving mechanism, both concerning error reporting

Improve error message

Document +RTS -xt

- Add a new flag, -xt, which enables inclusion of TSOs in a heap profile.

- Include large objects in heap profiles (except TSOs unless the -xt flag
  is given).

- In order to make this work, I had to set the bd->free field of the
  block descriptor for a large object to the correct value.  Previously,
  it pointed to the start of the block (i.e. the same as bd->start).
  I hope this doesn't have any other consequences; it looks more
  correct this way in any case.

A nullary constructor in an argument position should refer to the
constructor worker, not the wrapper.  In most cases they're the same,
but when using -funbox-strict-fields (or maybe a context on a data
type?) they can be different, leading to a crash.

MERGE TO STABLE

Increase the size of a string literal; cures a simplifier loop
    when an application (f "x") appeared to have size 1, and so was
    inlined repeatedly.  The problem was that "x" appeared to have
    size 0.

Fix two really bad typos in the Mac OS X specific code

MERGE TO STABLE

- Add sendfile-API for pumping out data via sendfile(2)
  Currently supported are Linux (tested) & FreeBSD (not tested yet), others
  will throw a runtime error until I get around to implement a fallback.

mingw: use cp's -u flag when copying over hi-boot files (or not, as the case might be now.)

for mingw builds, redirect to NUL

Set $(way_) and $(_way) in here, so they are available as soon as possible.

Fix to previous commit

Clean up properly after generating Haddock docs.

------------------------------------
	(a) Improve reporting of staging errors
	(b) Tidy up the construction of dict funs
			and default methods
	------------------------------------

Bale out earlier if main is not in scope (fixes several test failures)

The hook NoRunnableThreads() is not used; kill it.

wibble

Comment

--------------------------------
	Don't export the inlining for a foreign
	import that has a #include directive
	--------------------------------

Reason for this change: if the inlining is imported into another
module, the latter may not have the right #include directives.

Also add notes to the documentation to explain the issues.

------------------------------------
	Type signature for derived con2tag
	------------------------------------

		MERGE TO STABLE

The derived con2tag didn't have a type signature, so we got

	con2tagFoo :: a -> Int#
	con2tagFoo = \x -> getTag x

The getTag generates a case expression, so we get a polymorphic
case.  The polymorphic case simply does not work in *interpreted*
GHC 5.02.3 and as a result neither does con2tag.  Alas.

This commit fixes the problem, by giving a type signature for
con2TagFoo.  But note that getTag in interpreted GHC 5.02 will continue
to fail if used in a polymorphic context.  This problem does not arise
in the HEAD (eval/apply) so I'm going to leave it as a wont-fix bug.