scsh installation library

Introduction
------------

This is the scsh installation library, which aims at making it easy to
install extension libraries for scsh.

The complete documentation for this library can be found in
doc/install-lib.pdf. Apart from describing the library itself, this
document also explains how to install and use scsh packages in
general. At least Sections 3 and 4 of this document should be read
before proceeding further.

Notice that this library needs scsh v0.6.6 or newer, and will not
work at all with older versions.


Installation
------------

This library must be installed before any attempt at installing scsh
packages is made.

Since version 1.1, this library installs itself as a scsh package
called "install-lib", and additonally installs a small wrapper script
called "scsh-install-pkg", to install other packages later.

Installation is performed by running the "install.scm" script found in
the same directory as the present file. This script must at least be
provided with the following parameter:

  --prefix <dir>

    The prefix directory in which the "install-lib" package is to be
    installed. Please notice that this is *NOT* exactly the same as
    configure's prefix.

    Ideally, you should choose one prefix now and then stick to it
    when installing further packages, as this will greatly simplify
    their use.

Optionally, the directory in which to install the wrapper script
("scsh-install-pkg") can be specified using the "--bindir" option. By
default, the directory in which scsh itself is installed will be used.

Other parameters can also be supplied (--help, --layout, --verbose,
--dest-dir, etc.), as explained in the documentation.

As an example, to install everything in /usr/local one could invoke
the installation script as follows:

  ./install.scm --bindir /usr/local/bin --prefix /usr/local/share/scsh

This would install the following files (where <v> stands for the
current version of the installation library, e.g. 1.0.0):

  /usr/local/bin/scsh-install-pkg

    The script to run in order to install scsh packages. Its use is
    explained in the documentation.

  /usr/local/share/scsh/0.6/install-lib-<v>/scheme/install-lib-module.scm
  /usr/local/share/scsh/0.6/install-lib-<v>/scheme/install-lib-version.scm
  /usr/local/share/scsh/0.6/install-lib-<v>/scheme/install-lib.scm
  /usr/local/share/scsh/0.6/install-lib-<v>/load.scm

    The Scheme code for the installation library.

  /usr/local/share/scsh/0.6/install-lib

    A link pointing to /usr/local/share/scsh/0.6/install-lib-<v>,
    used to designate the current version of this package.

  /usr/local/share/scsh/0.6/install-lib-<v>/doc/pdf/install-lib.pdf

    The documentation describing the installation library, and how to
    manage scsh packages in general.