This is a description of how to generate and how to use the new
'pre-generated' system.

How to generate
---------------

In the source tree there is scrit 'src/scripts/mkdist.sh'.  This
script is used to make releases.  Normal use is

  path_to/mkdist.sh --copy-lisp --copy-phts --copy_help=path_to_help

where 'path_to/mkdist.sh' is full pathname of the script, 'path_to_help'
is path to directory containing help files (they are _not_ generated
by build process).  The script should be invoked in build directory
after out-of-source build.  It creates 'dist' subdirectory which
contains (tree of) files that should go into distribution tarball. 

Other options can be used to generate variants, where some but
not all parts are pregenerated.

Alternatively, FriCAS build system comes with a new make target "dist" which
creates a full source tarball together with pre-generated
machine-independent data that speed up the build process.

The command "make dist" has to be executed in an out-of-source build
after completion of a full successful build. Furthermore, the source
tree must be a clean checkout from the repository (SVN or GIT), since
all files in this tree will be copied into the distribution.

It creates a file fricas-VERSION.tar.bz2 where VERSION corresponds
to the second argument of AC_INIT in configure.ac.

Currently, one cannot simply call "make dist", but must provide a
location for the directory of
(not-yet-generated) .help files. The typical invocation is thus:

  make helpsrcdir=/path/to/spadhelp dist

The generated tarball will contain a "pre-generated" subdirectory with all the
machine-independent pre-generated files.

How to use
----------

FriCAS can be configured to used machine-independent files from an
earlier compilation.

In short, the Makefile variable PREGENERATED must either be empty
(then no pre-generated data is used) or contain the absolute path of
the directory of pre-generated data.

There are several ways to let the FriCAS build system know about where
the pre-generated data is located. In each case the build system
assumes that the provided data is sane and does not explicitly check.

1) If there is a subdirectory "pre-generated" inside the FriCAS source
   tree, then configure will automatically set PREGENERATED to point
   to this directory.
2) If configure is called with
   --with-pre-generated=/absolute/path/to/pre-generated, then
   PREGENERATED is set  to /absolute/path/to/pre-generated.
3) One can call make like
     make PREGENERATED=/absolute/path/to/pre-generated
   which does the obvious thing.