=head1 USE
The C<base_dir> statement is deprecated. It persists to support tests
which want to place their generated output in out of the way places for
clutter reduction and easier cleanup.
If you do use it, it will only affect initial generation with -c.
Then it specifies the parent of the build directory. By default that
is the current directory.
The C<base_dir> must already exist. To also control the name of the
build dir, use the deprecated C<app_dir> (but please don't).
=head1 EXAMPLE
To see an example, build:
bigtop -c example.bigtop all
Note that the build directory is called C<useless_dir> instead of C<Kids>.