An interface to call PHCpack from C functions in PHCv2.4.85

This directory was created in release 2.1 to call the Pieri homotopies
from C programs and for parallel implementations of the path trackers.
In release 2.3, the code was splitted among two subdirectories:
(1) Funky, a functional interface: C -> Ada -> C; and
(2) State, a state machine usage:  C <-> Ada.

In version 2.4.85, the folder Types was added with the definitions
of C types equivalent to the basic types in Ada.
The folder Structures defines packages to wrap systems and solutions.

   CtoPHC               : 6. interface from C to phc
      |-- Types         : 6.1. C types equivalent to Ada
      |-- Structures    : 6.2. system and solution wrappers
      |-- Funky         : 6.3. functional interface, C -> Ada -> C 
      |-- State         : 6.4. state machine gateway, C <-> Ada

While in both cases, the main program is written in C and calls an
Ada procedure, the two subdirectories implement two fundamentally
different types of interfaces.  

In (1), actual data is passed from the C function to the Ada procedure.
To process the results, the Ada procedure calls another C function. 
The interface programmer thus provides the main program and functions
to process the output provided by the Ada software.  This type of
interface is efficient, but requires either a programmer knowledgable
of both C and Ada, or two programmers collaborating with each other.

In (2), the data passed from the C function to the Ada procedure is
more generic in nature.  The Ada procedure operates as a gateway
interface to PHCpack.
