Declare rtsSupportsBoundThreads() here.

This change should have gone through with the threaded RTS I/O changes
yesterday.

Threaded RTS improvements:

 - Unix only: implement waitRead#, waitWrite# and delay# in Haskell,
   by having a single Haskell thread (the IO manager) performing a blocking
   select() operation.  Threads communicate with the IO manager
   via channels.  This is faster than doing the select() in the RTS,
   because we only restart the select() when a new request arrives,
   rather than each time around the scheduler.

   On Windows we just make blocking IO calls, we don't have a fancy IO
   manager (yet).

 - Simplify the scheduler for the threaded RTS, now that we don't have
   to wait for IO in the scheduler loop.

 - Remove detectBlackHoles(), which isn't used now (not sure how long
   this has been unused for... perhaps it was needed back when main threads
   used to be GC roots, so we had to check for blackholes manually rather
   than relying on the GC.)

Signals aren't quite right in the threaded RTS.  In fact, they're
slightly worse than before, because the thread receiving signals might
be blocked in a C call - previously there always be another thread
stuck in awaitEvent() that would notice the signal, but that's not
true now.  I can't see an easy fix yet.

Undo part of previous commit, a little testing code sneaked in and
broke all the GHCi tests.

Had enough of 'make boot' completely rebuilding gmp/ each time around.

---------------------------------
	Add lists to valid derivable methods
	---------------------------------

	(It'd be nice to merge this into the stable
	branch. It is an increase in functionality, but
	it's quite separate from everything else.)

Lists are useful in derivable type classes.  E.g. methods like

	class Shrinkable a where
	  op :: a -> [a]

This commit adds them, to join functions and tuples.

Remove dead code tcSplitMethodTy

---------------------------------
	Fix bug in derivable type classes
	---------------------------------

		MERGE TO STABLE (if poss)

The test for not-supported method types for derivable type classes
was broken. This fixes it.

Fixes to readline detection and use.
VS: ----------------------------------------------------------------------

Detect whether $(GHC) supports the readline package.

Improve error message

Fix typo; fixes simpl007

genericRaise() hack needed on FreeBSD too.

Fixed some links

Fixed typo

Comments only

------------------------------------------------------
	Fix an interaction between zonking of Insts and GADTs
	------------------------------------------------------

Insts float outwards, perhaps out of the scope of a type-refining GADT case.
So we have to make sure they are fully zonked wrt the type refinement.

tcSimplifyCheck does this, but there were two omissions
a) the tcInstStupidTheta in TcPat.tcConPat didn't get zonked
b) a Dict and Lit Inst contained an Id that wasn't zonked, to save work

To fix (b), Insts have a little less cached info; the Name is held instead
of the Id, so that the Id doesn't need to be zonked.

One test in typecheck/should_compile/tc182

FreeBSD needs -optl-pthread for the threaded way

HsNoBang should simply be omitted; fixes a TH_spliceDecl2 test

Fix missing case for algTyConRhs; fixes test ghci011

Complain about GADTs if not -fglasgow-exts

Make the sed command turning '#define PACKAGE_FOO "blah"' into
'/* #undef PACKAGE_FOO */' more portable, though a tad less precise.

The use of \| deep inside the pattern is a GNU extension (from sed 2.05).

For platforms with no PIC method defined, use
LabelAccessStyle of AccessDirectly, in howToAccessLabel.
This seems to keep the ncg working on OpenBSD.

Is this the correct default, Wolfgang?

Add missing final #else case for howToAccessLabel.

Wibbles to hi-boot files and newtypes

Position Independent Code and Dynamic Linking Support, Part 1

This commit allows generation of position independent code (PIC) that fully supports dynamic linking on Mac OS X and PowerPC Linux.
Other platforms are not yet supported, and there is no support for actually linking or using dynamic libraries - so if you use the -fPIC or -dynamic code generation flags, you have to type your (platform-specific) linker command lines yourself.


nativeGen/PositionIndependentCode.hs:
New file. Look here for some more comments on how this works.

cmm/CLabel.hs:
Add support for DynamicLinkerLabels and PIC base labels - for use inside the NCG.
needsCDecl: Case alternative labels now need C decls, see the codeGen/CgInfoTbls.hs below for details

cmm/Cmm.hs:
Add CmmPicBaseReg (used in NCG),
and CmmLabelDiffOff (used in NCG and for offsets in info tables)

cmm/CmmParse.y:
support offsets in info tables

cmm/PprC.hs:
support CmmLabelDiffOff
Case alternative labels now need C decls (see the codeGen/CgInfoTbls.hs for details), so we need to pprDataExterns for info tables.

cmm/PprCmm.hs:
support CmmLabelDiffOff

codeGen/CgInfoTbls.hs:
no longer store absolute addresses in info tables, instead, we store offsets.
Also, for vectored return points, emit the alternatives _after_ the vector table. This is to work around a limitation in Apple's as, which refuses to handle label differences where one label is at the end of a section. Emitting alternatives after vector info tables makes sure this never happens in GHC generated code. Case alternatives now require prototypes in hc code, though (see changes in PprC.hs, CLabel.hs).

main/CmdLineOpts.lhs:
Add a new option, -fPIC.

main/DriverFlags.hs:
Pass the correct options for PIC to gcc, depending on the platform. Only for powerpc for now.

nativeGen/AsmCodeGen.hs:
Many changes...
Mac OS X-specific management of import stubs is no longer, it's now part of a general mechanism to handle such things for all platforms that need it (Darwin [both ppc and x86], Linux on ppc, and some platforms we don't support).
Move cmmToCmm into its own monad which can accumulate a list of imported symbols. Make it call cmmMakeDynamicReference at the right places.

nativeGen/MachCodeGen.hs:
nativeGen/MachInstrs.hs:
nativeGen/MachRegs.lhs:
nativeGen/PprMach.hs:
nativeGen/RegAllocInfo.hs:
Too many changes to enumerate here, PowerPC specific.

nativeGen/NCGMonad.hs:
NatM still tracks imported symbols, as more labels can be created during code generation (float literals, jump tables; on some platforms all data access has to go through the dynamic linking mechanism).

driver/mangler/ghc-asm.lprl:
Mangle absolute addresses in info tables to offsets.
Correctly pass through GCC-generated PIC for Mac OS X and powerpc linux.

includes/Cmm.h:
includes/InfoTables.h:
includes/Storage.h:
includes/mkDerivedConstants.c:
rts/GC.c:
rts/GCCompact.c:
rts/HeapStackCheck.cmm:
rts/Printer.c:
rts/RetainerProfile.c:
rts/Sanity.c:
Adapt to the fact that info tables now contain offsets.

rts/Linker.c:
Mac-specific: change machoInitSymbolsWithoutUnderscore to support PIC.

Check for shell scripts first - they don't exist on my Windows nightly build.

Need suffix.mk, otherwise .hc bootstrapping dies in ghc/compiler, with
"No rule to make target Foo.o" error.

Use XML mode, not SGML

Use >> append onto build.mk, so that build scripts can add extra vars
to build.mk.

Replace grep \(a\|b\) with [ab]. \| is an extended regex, whereas the
[] class is a basic RE -- so it works with BSD grep.

Document -ferror-spans

Report bogus strictness annotation on newtype

------------------------------------
	Part-fix an awkward interaction
	between case-of-case and GADTs
	------------------------------------

Consider
	data T a where
	  MkT :: a -> b -> T a

	f = /\a. \(w::a).
	   case (case ...) of
		  MkT a' b (p::a') (q::b) -> [p,w]

The danger is that we'll make a join point

	j a' p = [p,w]

and that's ill-typed, because (p::a') but (w::a).

Solution so far: don't abstract over a', because the type refinement
maps [a' -> a] .  Ultimately that won't work when real refinement goes on.

Then we must abstract over any refined free variables.  Hmm.  Maybe we
could just abstract over *all* free variables, thereby lambda-lifting
the join point?   We should try this.

Sort decls in cycle for error message

Better reporting of duplicate top-level defns

Make combineSrcSpans commutative

Improve error locations for binding conflicts

Warning police. Move prototype of genericRaise into RtsExternal.h, so
the libraries can see it.

Mac OS X:
Make the Linker deal properly with object files that lack a symbol table or
a dynamic symbol table.
Objects that don't import any symbols don't get a dynamic symbol table,
which caused GHCi to crash.

MERGE TO STABLE

Warning police (added missing #include)

Warning police (bring 'raise' into scope)