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Fix compilation problem on mingw32

Fix compilation breakage with GHC 4.08.x.

Three Template Haskell improvements

a) Add type synonyms to THSyntax (and DsMeta, Convert)

b) Make Q into a newtype instead of a type synonym

c) Eliminate tiresome and error prone argument to DsMeta.wrapGenSyms
   and similarly addTyVarBinds

More tidy up

deja vu all over again

Fix build on GHC < 5.00

Restore interrupt/quit signal handlers after every evaluation in GHCi,
just in case the program set its own.

Be sensitive to filenames containing spaces when processing
:load & :add commands. Ditto when interpreting filenames given
on GHCi's cmd-line.

Merge to STABLE.

Further refine the criteria for deciding whether command line
arguments should be passed to the compilation manager or the linker.
See comments in the file.

MERGE TO STABLE

On second thoughts, use memcmp instead.

Oops, cmpFS uses strcmp() to compare strings, so it has a '\0'
terminator requirement.  Fix it to use strncmp() instead.

Fix recent breakage on the HEAD.  This was caused by the fix to
Lex.lhs to treat primitive strings as "narrow" FastStrings in all
cases, rather than Unicode ("wide") FastStrings if the string
contained a '\0'.  The problem is that narrow FastStrings aren't set
up to handle strings containing '\0'.  They used to be, but it got
broken somewhere along the line.

This commit:

 - remove the '\0' test from unpackCStringBA (it takes a length
   argument anyway), and rename it to unpackNBytesBA.  This fixes
   the bug.

 - remove the '\0' terminator from all strings generated by the
   functions in PrimPacked.  The terminators aren't required,
   as far as I can tell.  This should have a tiny but positive
   effect on compile times.

MERGE TO STABLE

Fix to build with 4.08.x

Use ioError instead of throw for IOErrors, in anticipation of
a change from IOError = Exception to IOError = IOException.

------------------
  	   Fix a newtype-deriving bug
		------------------

The new newtype-deriving mechanism was erroneously using the
*representation type* of the newtype.  The rep type looks through all
ihtermediate newtypes, so that is wrong.  See Note [newtype
representation] in TcDeriv.lhs

deriving/should_run/drvrun013 now tests for this.

Move looksLikeModuleName here from InterativeUI, so we can use it elsewhere.

Don't need to export Exception.try or Exception.throwDyn here.

make it compile again with 4.08.x

Compatibility fixes for Exception.try

--------------------------------
        Implement recursive do-notation
	--------------------------------

This commit adds recursive do-notation, which Hugs has had for some time.

	mdo { x <- foo y ;
	      y <- baz x ;
	      return (y,x) }

turns into

	do { (x,y) <- mfix (\~(x,y) -> do { x <- foo y;
					    y <- baz x }) ;
	     return (y,x) }

This is all based on work by Levent Erkok and John Lanuchbury.

The really tricky bit is in the renamer (RnExpr.rnMDoStmts) where
we break things up into minimal segments.  The rest is easy, including
the type checker.

Levent laid the groundwork, and Simon finished it off. Needless to say,
I couldn't resist tidying up other stuff, so there's no guaranteed I
have not broken something.

Fix up exception handling when reading an interface file, and make it
compile with 4.08.x again.

GhcExceptions weren't being caught by readIface, so an error when
reading an interface could be unintentionally fatal (errors should be
soft when reading the old interface file for the current module).
Also, the Interrupted exception should not be caught by readIface,
because we want ^C to behave as normal when reading interface files
(currently it causes an interface-file read error rather than
interrupting the whole compiler).

Some exception-related compatibility functions have been moved from
Util to Panic.

--------------------------------------
	Make Template Haskell into the HEAD
	--------------------------------------

This massive commit transfers to the HEAD all the stuff that
Simon and Tim have been doing on Template Haskell.  The
meta-haskell-branch is no more!

WARNING: make sure that you

  * Update your links if you are using link trees.
    Some modules have been added, some have gone away.

  * Do 'make clean' in all library trees.
    The interface file format has changed, and you can
    get strange panics (sadly) if GHC tries to read old interface files:
    e.g.  ghc-5.05: panic! (the `impossible' happened, GHC version 5.05):
	  Binary.get(TyClDecl): ForeignType

  * You need to recompile the rts too; Linker.c has changed


However the libraries are almost unaltered; just a tiny change in
Base, and to the exports in Prelude.


NOTE: so far as TH itself is concerned, expression splices work
fine, but declaration splices are not complete.


		---------------
		The main change
		---------------

The main structural change: renaming and typechecking have to be
interleaved, because we can't rename stuff after a declaration splice
until after we've typechecked the stuff before (and the splice
itself).

* Combine the renamer and typecheker monads into one
	(TcRnMonad, TcRnTypes)
  These two replace TcMonad and RnMonad

* Give them a single 'driver' (TcRnDriver).  This driver
  replaces TcModule.lhs and Rename.lhs

* The haskell-src library package has a module
	Language/Haskell/THSyntax
  which defines the Haskell data type seen by the TH programmer.

* New modules:
	hsSyn/Convert.hs 	converts THSyntax -> HsSyn
	deSugar/DsMeta.hs 	converts HsSyn -> THSyntax

* New module typecheck/TcSplice type-checks Template Haskell splices.

		-------------
		Linking stuff
		-------------

* ByteCodeLink has been split into
	ByteCodeLink	(which links)
	ByteCodeAsm	(which assembles)

* New module ghci/ObjLink is the object-code linker.

* compMan/CmLink is removed entirely (was out of place)
  Ditto CmTypes (which was tiny)

* Linker.c initialises the linker when it is first used (no need to call
  initLinker any more).  Template Haskell makes it harder to know when
  and whether to initialise the linker.


	-------------------------------------
	Gathering the LIE in the type checker
	-------------------------------------

* Instead of explicitly gathering constraints in the LIE
	tcExpr :: RenamedExpr -> TcM (TypecheckedExpr, LIE)
  we now dump the constraints into a mutable varabiable carried
  by the monad, so we get
	tcExpr :: RenamedExpr -> TcM TypecheckedExpr

  Much less clutter in the code, and more efficient too.
  (Originally suggested by Mark Shields.)


		-----------------
		Remove "SysNames"
		-----------------

Because the renamer and the type checker were entirely separate,
we had to carry some rather tiresome implicit binders (or "SysNames")
along inside some of the HsDecl data structures.  They were both
tiresome and fragile.

Now that the typechecker and renamer are more intimately coupled,
we can eliminate SysNames (well, mostly... default methods still
carry something similar).

		-------------
		Clean up HsPat
		-------------

One big clean up is this: instead of having two HsPat types (InPat and
OutPat), they are now combined into one.  This is more consistent with
the way that HsExpr etc is handled; there are some 'Out' constructors
for the type checker output.

So:
	HsPat.InPat	--> HsPat.Pat
	HsPat.OutPat	--> HsPat.Pat
	No 'pat' type parameter in HsExpr, HsBinds, etc

	Constructor patterns are nicer now: they use
		HsPat.HsConDetails
	for the three cases of constructor patterns:
		prefix, infix, and record-bindings

	The *same* data type HsConDetails is used in the type
	declaration of the data type (HsDecls.TyData)

Lots of associated clean-up operations here and there.  Less code.
Everything is wonderful.

Put debugging output in #ifdef DEBUG

MERGE TO STABLE

Finally separate the compiler from hslibs.

Mainly import wibbles, and use the new POSIX library when
bootstrapping.

Remove unused import of PrelPack (should fix the build again)

Housekeeping:

  - The main goal is to remove dependencies on hslibs for a
    bootstrapped compiler, leaving only a requirement that the
    packages base, haskell98 and readline are built in stage 1 in
    order to bootstrap.  We're almost there: Posix is still required
    for signal handling, but all other dependencies on hslibs are now
    gone.

    Uses of Addr and ByteArray/MutableByteArray array are all gone
    from the compiler.  PrimPacked defines the Ptr type for GHC 4.08
    (which didn't have it), and it defines simple BA and MBA types to
    replace uses of ByteArray and MutableByteArray respectively.

  - Clean up import lists.  HsVersions.h now defines macros for some
    modules which have moved between GHC versions.  eg. one now
    imports 'GLAEXTS' to get at unboxed types and primops in the
    compiler.

    Many import lists have been sorted as per the recommendations in
    the new style guidelines in the commentary.

I've built the compiler with GHC 4.08.2, 5.00.2, 5.02.3, 5.04 and
itself, and everything still works here.  Doubtless I've got something
wrong, though.

printDump,printErrs,printSDoc: flush stdout and stderr

In hPutLitString, catch the empty string case before calling hPutBuf.
Some older versions of hPutBufFull choke on a zero-length buffer.

Fixes occasional problems with the Sparc native code generator, which
uses SLIT("") in a couple of places.

Use Unique.getKey instead of Unique.u2i (they are the same function).

speakNth works for 11,12,13

Include hschooks.h via a global option to get ghc_strlen's
prototype. It's too omnipresent for per-file OPTIONS.

Re-enable bootstrapping: More Ptr trouble, now that it's (almost) abstract...

In the get method for FastString, do the dictionary lookup strictly
(speeds things up and reduces the residency by a few k).

- When converting ModuleNames to Modules for use in the the module
  initialisation code, look them up in the IfaceTable(s) instead of
  calling findModule again.  They are guaranteed to be in either
  the HomeIfaceTable or the PackageIfaceTable after the renamer,
  so this saves some trips to the filesystem.  Also, move this
  code earlier in the compilation cycle to avoid holding on to the
  renamed syntax for too long (not sure if this makes a difference or
  not, but it definitely looked space-leakish before).

- remove Util.unJust, it is a duplicate of Maybes.expectJust

- Fix bootstrapped compilation,

- Add the following RULE:

	text "abc"  ==> ptext SLIT("abc")

  so most of the time there shouldn't be any need to use SLIT().
  I'll go around and apply the opposite of the above RULE once
  I've convinced myself that the RULE does what it should.

FastString cleanup, stage 1.

The FastString type is no longer a mixture of hashed strings and
literal strings, it contains hashed strings only with O(1) comparison
(except for UnicodeStr, but that will also go away in due course).  To
create a literal instance of FastString, use FSLIT("..").

By far the most common use of the old literal version of FastString
was in the pattern

	  ptext SLIT("...")

this combination still works, although it doesn't go via FastString
any more.  The next stage will be to remove the need to use this
special combination at all, using a RULE.

To convert a FastString into an SDoc, now use 'ftext' instead of
'ptext'.

I've also removed all the FAST_STRING related macros from HsVersions.h
except for SLIT and FSLIT, just use the relevant functions from
FastString instead.

Define out-of-line versions of strlen and memcmp for PrimPacked, and
remove the -monly-2-regs flag.

Replace strncmp() with memcmp() for comparing non-zero-terminated strings.

-------------------
	Mainly derived Read
	-------------------

This commit is a tangle of several things that somehow got wound up
together, I'm afraid.


The main course
~~~~~~~~~~~~~~~
Replace the derived-Read machinery with Koen's cunning new parser
combinator library.   The result should be
	* much smaller code sizes from derived Read
	* faster execution of derived Read

WARNING: I have not thoroughly tested this stuff; I'd be glad if you did!
	 All the hard work is done, but there may be a few nits.

The Read class gets two new methods, not exposed
in the H98 inteface of course:
  class Read a where
    readsPrec    :: Int -> ReadS a
    readList     :: ReadS [a]
    readPrec     :: ReadPrec a		-- NEW
    readListPrec :: ReadPrec [a]	-- NEW

There are the following new libraries:

  Text.ParserCombinators.ReadP		Koens combinator parser
  Text.ParserCombinators.ReadPrec	Ditto, but with precedences

  Text.Read.Lex				An emasculated lexical analyser
					that provides the functionality
					of H98 'lex'

TcGenDeriv is changed to generate code that uses the new libraries.
The built-in instances of Read (List, Maybe, tuples, etc) use the new
libraries.


Other stuff
~~~~~~~~~~~
1. Some fixes the the plumbing of external-core generation. Sigbjorn
did most of the work earlier, but this commit completes the renaming and
typechecking plumbing.

2. Runtime error-generation functions, such as GHC.Err.recSelErr,
GHC.Err.recUpdErr, etc, now take an Addr#, pointing to a UTF8-encoded
C string, instead of a Haskell string.  This makes the *calls* to these
functions easier to generate, and smaller too, which is a good thing.

In particular, it means that MkId.mkRecordSelectorId doesn't need to
be passed "unpackCStringId", which was GRUESOME; and that in turn means
that tcTypeAndClassDecls doesn't need to be passed unf_env, which is
a very worthwhile cleanup.   Win/win situation.

3.  GHC now faithfully translates do-notation using ">>" for statements
with no binding, just as the report says.  While I was there I tidied
up HsDo to take a list of Ids instead of 3 (but now 4) separate Ids.
Saves a bit of code here and there.  Also introduced Inst.newMethodFromName
to package a common idiom.

Friday afternoon pet peeve removal: define (Util.notNull :: [a] -> Bool) and use it