Not changing type of target_dim as shape related

and fixed warnings that came with the conversion

We introduce DBUG_UNREACHABLE macro to mark the places in the code
that must not happen.  We produce an error message stating that we
hit such a place in the code.

    * debug.[ch]:    DBUG_UNREACHABLE macro defined for both DBUG_OFF
                     and !DBUG_OFF cases.

                     exit_function was moved outside of !DBUG_OFF
                     region.

    * ctinfo.[ch]:   Removed CTIterminateCompilationSilient in favour
                     of existing CTIexit and replaced occurences.

    * main.c         Adjusted comments to match doxygen style, set
                     exit_function unconditionally to DBUG_OFF.

After migration to git the annotations became useless, as they cannot be
expanded under git.  Part of the annotations were wrong even under svn.
As for logs, all the logs can be retrieved per file using
git log <filename>

then GENARRAY_SHAPE of that WL is AKV.

A recent extension to WLPROP, allowing it to work on CONDFUNS
(not checked in yet), causes an assert failure in WLF, because the 
producerWL, when copied into the CONDFUN, has AKS result
shape, but GENARRAY_SHAPE, now an N_arg to the CONDFUN,
is no longer AKV, because WLBSC got its fingers in the pie,
and generates an AKS N_array for that shape.

The change here merely makes the GENARRAY_SHAPE check for AKV
early enough that WLF does not attempt to perform the fold.

Presumably, on another trip through CYC/SAACYC, things
will untangle and the WLF will happen.

  to get memory usage statistics you now have to turn on memcheck, 
    which is only available on the development version of the compiler.
changed ifdef property of ast.xml to ifndef, in order to replace the SHOW_MALLOC
  macro with DEBUG_OFF. This way, the check memory traversal is not compiled
  in the production version of the compiler.

new naming scheme to compound access macros defined in tree_compound.h.

Vardecs and Assigns. This long overdue cleanup in the AST representation
required substantial changes throughout the compiler to remove all the
code that was particularly concerned with avoiding empty assignment chains
and recreating them where necessary. Creating and removing N_empty nodes 
is now avoided, and the code has become much leaner and simpler in numerous
compiler modules.

accordingly ASSIGN_INSTR into ASSIGN_STMT. The original situation was 
particularly confusing as BLOCK_INSTR did not point to anything of
node set Instr. 
I hope this is a small contribution to making the AST better digestible
to newcomers and godfathers alike.

has two child nodes: Vardecs (instead of Vardec) and Assigns
(instead of Instr).

1. -ssaiv enables code to force WL index variables
   into SSA form. This definitely kills WLF today, 
   manifesting itself as references to undefined IVs.
   If you use it with -nowlf, you may get further.

2. -doswlf extended:
  - Operates on multiple WL partitions in both folder
    and foldee WLs.

  - Maps modarray(foldee) WLs into genarray(shape(foldee)),
    to eliminate reference to foldee data.

  - Slightly improved analysis of WL bounds. However,
    the whole array shapes and bounds
    thing remains a dog's breakfast. 

Operation to invoke extended WLF requires:

 -ssaiv -doswlf -dosaa

and may also require

 -nowlf

   but I want to get some stuff checked in. Theoretically, this is
   all enabled only with sac2c option -ssaiv. The intent is to make
   that option go away, and to make flattened code the standard for
   all code in the above phases.

2. -d treecheck code to detect non-flattened GENERATOR_BOUND1 and
   GENERATOR_BOUND2, which are the only ones I absolutely need to
   be flattened, at present.

and the associated ICMs renamed to fully qualified names:
dim_A, shape_A, sel_VxA, reshape_VxA, modarray_AxVxS.

However, internal_lib itself has not yet been removed from system.

new compiler module support/math_utils.

compiler module support/str.
Extended refactoring mechanism by additional condition.

This is necessary for the improved tree sanity checks
in traverse.c

added new attribute ARRAY_BASETYPE to capture the scalar type of the array's elements (as used in new_types.h). 
This is of special importance for the empty array [].
Two utility functions TCmakeVector and TCmakeIntVector were added to tree_compound for convenience.

Removed printing on OPT as the required output is generated automatically by PHrunCompilerOptimizationInCycle.