There's only a single compiler backend now, so the 'z' suffix means
nothing. Also, the flags were confusingly named ('cmm-foo' vs
'foo-cmm',) and counter-intuitively, '-ddump-cmm' did not do at all what
you expected since the new backend went live.

Basically, all of the -ddump-cmmz-* flags are now -ddump-cmm-*. Some were
renamed to be more consistent.

This doesn't update the manual; it already mentions '-ddump-cmm' and
that flag implies all the others anyway, which is probably what you
want.
Signed-off-by: Austin Seipp <mad.one@gmail.com>

This fixes Trac #7368. The problem was that we were matching
   Bad w ~ f (Bad f)
where (f :: * -> *).  Thta leads to (w ~ Bad f), which is
ill-kinded, but matchExpectedTyConApp was returning the (Bad f)
as the argument type, and that was being used to instanatiate
w in the data constructor type, which is very bad.

The code also becomes simpler and easier to understand, which is
an excellent thing.

This fixes Trac #7503.

They properly belong in TysWiredIn, since they are defined in Haskell
in GHC.TypeLits.

Moveover, make them WiredIn (again as they should be) and use
checkWiredInTyCon when encountering them in TcHsType.tc_hs_type,
so that the interface file is loaded.  This fixes Trac #7502.

Nothing big here, just tidying up deetails

This reverts commit f184d9ca.

The next commit will fix it in a better way.

Fixes #7498.

On x86 and powerpc, the second form above was ignoring all the CPP
lines and hence trying to compile x86 asm on powerpc and powerpc asm
on x86.

I'm not sure if making an entirely new HscEnv is too large a hammer,
but it works for now.

Conflicts:
	compiler/typecheck/TcTyClsDecls.lhs

The situation was pretty dire.  The way in which data constructors
were handled, notably the mapping between their *source* argument types
and their *representation* argument types (after seq'ing and unpacking)
was scattered in three different places, and hard to keep in sync.

Now it is all in one place:

 * The dcRep field of a DataCon gives its representation,
   specified by a DataConRep

 * As well as having the wrapper, the DataConRep has a "boxer"
   of type DataConBoxer (defined in MkId for loopy reasons).
   The boxer used at a pattern match to reconstruct the source-level
   arguments from the rep-level bindings in the pattern match.

 * The unboxing in the wrapper and the boxing in the boxer are dual,
   and are now constructed together, by MkId.mkDataConRep. This is
   the key function of this change.

 * All the computeBoxingStrategy code in TcTyClsDcls disappears.

Much nicer.

There is a little bit of refactoring left to do; the strange
deepSplitProductType functions are now called only in WwLib, so
I moved them there, and I think they could be tidied up further.

Working towards removing FastBytes

it was only needed for registerised compilation.

A step on the way to getting rid of FastBytes

slow nofib Compile times look like:
    -1 s.d.   -2.4%
    +1 s.d.   +3.4%
    Average   +0.4%
but looking at the times for the longer-running compilations I think the
change is just noise.

Slow nofib Compile Times difference looks like just noise:
-1 s.d.        -2.9%
+1 s.d.        +2.9%
Average        -0.1%