By default, files are installed into this structure. It matches the
World According to Stallman, aka the GNU filesystem standard.

A "feature" of this standard is to scatter files around the file system
depending on their purpose. This map is my attempt to document where
everything ends up and why.

The exact locations depend on arguments given to configure when compiling.
Type './configure --help' for a summary of available options. See also
comments after the map.

Some of the directories in this tree are empty. They are included here
because they are defined in the GNU FSS.

/usr
|-/include
`-/local [1][2]
  |-/bin [3]		siag, pw, egon executables
  |-/sbin
  |-/lib [4]
  | `-/siag
  |   `-/plugins	plugins (all of them)
  |-/share [5]
  | |-/siag
  | | |-/siod		SIOD runtime library
  | | |-/common		Dictionaries, common Scheme libraries
  | | |-/xcommon	Scheme libraries for X support
  | | |-/plugins	Scheme libraries for plugins
  | | |-/siag		Scheme for all versions of Siag
  | | |-/xsiag		Scheme for Xt version of Siag
  | | |-/pw		you get the picture...
  | | |-/xpw
  | | |-/egon
  | | `-/xegon
  | `-/emacs
  |   `-/site-lisp
  |-/etc
  |-/com
  |-/var
  |-/lib		nothing
  |-/info
  |-/include
  |-/man [6]
  | `/man1		siag.1, pw.1, egon.1, image_plugin.1
  `-/doc
    `-/siag
      |-/siod		SIOD docs
      |-/common		Common docs
      |-/xcommon	Common X docs
      |-/siag		Siag docs
      | `-/examples	Siag examples
      |-/xsiag		Xt Siag docs
      |-/pw		PW docs
      | `-/examples	PW examples
      |-/xpw		Xt PW docs
      |-/egon		Egon docs
      | `-/examples	Egon examples
      `-/xegon		Xt Egon docs

[1] prefix, default /usr/local
[2] exec-prefix, default ${prefix}
[3] bindir, default ${exec-prefix}/bin
[4] libdir, default ${exec-prefix}/lib
[5] datadir, default ${prefix}/share
[6] mandir, default ${prefix}/man

The following C preprocessor symbols are defined, along with their
default values:

LIBDIR="/usr/local/lib/siag"
DATADIR="/usr/local/share/siag"
DOCDIR="/usr/local/doc/siag"

The following C and SIOD string variables are set, along with their
default values:

libdir=LIBDIR
datadir=DATADIR
docdir=DOCDIR

The libdir variable is used to find plugins. The datadir is used to
find Scheme libraries. The docdir is used to find online documentation.
The docdir is a de facto standard extension to the GNU standard.

Important change: nothing is installed into the /usr/local/libexec
directory. Previous versions installed plugins there.

As usual, things are meant to be installed by typing "make install" and
not moved around manually afterwards. Putting files where Siag can't find
them will inevitably lead to loss of functionality and possibly loss of
data. However, it is possible to move the files if the environment
variables SIAGHOME and SIAGDOCS are used to tell Siag their new
whereabouts. If the variables are set, the following changes are
made to the directory structure:

$SIAGHOME
 |-/siod		SIOD runtime library
 |-/common		Dictionaries, common Scheme libraries
 |-/xcommon		Scheme libraries for X support
 |-/plugins		Plugins, scheme libraries for plugins
 |-/siag		Scheme for all versions of Siag
 |-/xsiag		Scheme for Xt version of Siag
 |-/pw			you get the picture...
 |-/xpw
 |-/egon
 `-/xegon

$SIAGDOCS
 |-/siod		SIOD docs
 |-/common		Common docs
 |-/xcommon		Common X docs
 |-/siag		Siag docs
 | `-/examples		Siag examples
 |-/xsiag		Xt Siag docs
 |-/pw			PW docs
 | `-/examples		PW examples
 |-/xpw			Xt PW docs
 |-/egon		Egon docs
 | `-/examples		Egon examples
 `-/xegon		Xt Egon docs

Setting the variables changes these C and SIOD variables in the
following way:

libdir=$SIAGHOME
datadir=$SIAGHOME
docdir=$SIAGDOCS

Simply put: $SIAGHOME contains the merged contents of
/usr/local/lib/siag and /usr/local/share/siag.
$SIAGDOCS contains the contents of /usr/local/docs/siag.

This exercise is not recommended. It is only meant for installing
pre-compiled binaries on systems where you are not root and recompiling
is not an option. Better solutions include:

 - become root
 - get a compiler
 - get a new system
 - grow tomatoes