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Fix via C compilation of modules that import, say, log1p from math.h (#3117)

The list is based on preprocessing Stg.h with glibc 2.6.1 headers, and
cross-checked with the ISO C 99 standard (draft).

- Reifying a type family returns a TH family declaration
- Reifying a data constructor from a data instance attributes that
  constructor to the family (not the representation tycon)
- Ideally, we should have facilities to reify all type/data instances of a 
  given family (and the same for instances of a class).  I haven't added that
  here as it involves some API design.

Please the -Wall police by moving a variable declaration; really FIX getNumberOfProcessors() for MacOS X

This checks if darwin_HOST_OS is defined and, if so, we call
sysctlbyname() on the "hw.ncpu" property to get the processor count.

I'm not sure if this is the correct fix.  If targetPlatform is really
NCG-specific, then maybe we should call it asmTargetPlatform or
something.

- yet another wrong calling convention; this one was a special case for returning one
  value.

- The function argument was stripped from the argument list but not from the type.
  Now they're both stripped.

1. Stack overflow fixed by making dataflow monad strict in the state.
2. Out of memory fixed by "forgetting" lastoutfacts in the dataflow monad
   where we should. We were creating an unnecessarily long list that grew
   exponentially...

This patch adds an optional CONLIKE modifier to INLINE/NOINLINE pragmas, 
   {-# NOINLINE CONLIKE [1] f #-}
The effect is to allow applications of 'f' to be expanded in a potential
rule match.  Example
  {-# RULE "r/f" forall v. r (f v) = f (v+1) #-}

Consider the term
     let x = f v in ..x...x...(r x)...
Normally the (r x) would not match the rule, because GHC would be scared
about duplicating the redex (f v). However the CONLIKE modifier says to
treat 'f' like a constructor in this situation, and "look through" the
unfolding for x.  So (r x) fires, yielding (f (v+1)).

The main changes are:
  - Syntax

  - The inlinePragInfo field of an IdInfo has a RuleMatchInfo
    component, which records whether or not the Id is CONLIKE.
    Of course, this needs to be serialised in interface files too.

  - The occurrence analyser (OccAnal) and simplifier (Simplify) treat
    CONLIKE thing like constructors, by ANF-ing them

  - New function coreUtils.exprIsExpandable is like exprIsCheap, but
    additionally spots applications of CONLIKE functions

  - A CoreUnfolding has a field that caches exprIsExpandable

  - The rule matcher consults this field.  See 
    Note [Expanding variables] in Rules.lhs.

On the way I fixed a lurking variable bug in the way variables are
expanded.  See Note [Do not expand locally-bound variables] in
Rule.lhs.  I also did a bit of reformatting and refactoring in
Rules.lhs, so the module has more lines changed than are really
different.

Generate binary log files from the RTS containing a log of runtime
events with timestamps.  The log file can be visualised in various
ways, for investigating runtime behaviour and debugging performance
problems.  See for example the forthcoming ThreadScope viewer.

New GHC option:

  -eventlog   (link-time option) Enables event logging.

  +RTS -l     (runtime option) Generates <prog>.eventlog with
              the binary event information.

This replaces some of the tracing machinery we already had in the RTS:
e.g. +RTS -vg  for GC tracing (we should do this using the new event
logging instead).

Event logging has almost no runtime cost when it isn't enabled, though
in the future we might add more fine-grained events and this might
change; hence having a link-time option and compiling a separate
version of the RTS for event logging.  There's a small runtime cost
for enabling event-logging, for most programs it shouldn't make much
difference.

(Todo: docs)

Since we introduced pointer tagging, we no longer always enter a
closure to evaluate it.  However, the biographical profiler relies on
closures being entered in order to mark them as "used", so we were
getting spurious amounts of data attributed to VOID.  It turns out
there are various places that need to be fixed, and I think at least
one of them was also wrong before pointer tagging (CgCon.cgReturnDataCon).

Somebody needs to implement getNumberOfProcessors() for MacOS X,
currently it will return 1.

Also remove some unused cruft

Fixes heapprof001(prof_hp) after fix for #2917

Fixes heapprof001(prof_hp) following the recent HpLim patch, which
depended on the lack of slop in the heap.