This directory may be used as a convenient location for the build directory
trees.  For example, it may contain subdirectories "Linux-i686" and
"Linux-x86_64".  Those directories in turn may contain subdirectories, if
desired, with names such as "ubuntu", "debian", and "ubuntu-debug", or even
"ubuntu/normal" and "ubuntu/debug", serving as the actual build directories.

A subdirectory "tarfiles" is used as a repository for downloaded source code of
third party libraries, in compressed archive format, shared among the various
build directories.  A further subdirectory, "LibrarySource", will probably be
introduced to hold the corresponding uncompressed directory trees, but just for
those libraries that support separate build directories using autoconf (as we
do).

A subdirectory "CommonStagingArea" is optionally and automatically used as a
place where files can be installed, in such a way that architecture-independent
files get made only once, saving time when versions for multiple architectures
are being built.

The path to the staging area may be specified explicitly by the user using the
"--with-staging-area" option of the "configure" script, or implicity using the
"--enable-common-staging-area" option.

The "make" target "all" will pre-install the files there, and the "make" target
"install" will copy the files from here to the final installation directory, if
there is one.  Alternatively, distribution files in tar, deb, rpm, etc.,
formats can be requested through options to configure, and they will be made by
the target "all".

Installations will be done here with the SeparateExec option to the
installPackage in Macaulay 2 set to true, so that all the
architecture-independent files are in a subdirectory of this directory called
"common", and the architecture-dependent files will be in other subdirectories,
such as "x86_64-Linux-Ubuntu-8.10".  (Actually, this is being changed...)
