-*-text-*-

The package uses both R's building system, and autoconf to organise
getting fftw found.  The full sequence of commands to run everything
is

  autoheader  # build src/config.h.in
  autoconf    # build configure
  ./configure # builds src/config.h and src/Makevars

The autoheader and autoconf steps should be done before packaging up
with R CMD build

To install and specify the location of the fftw library in a
non-standard place, a line like this is required:
  R CMD INSTALL diversitree --configure-args='--with-fftw=/path/to/fftw'
where the path will be the path so that the files
  /path/to/fftw/include/fftw3.h
  /path/to/fftw/lib/lib/fftw3.so
exist.

On Windows, set the environment variable LIB_FFTW to point to the
directory that contains include/fftw.h, and install the package.

If fftw is not found, installation will continue, but the (relatively)
fast C based QuaSSE integration will not be available.  The R based
fft integrator and the method-of-lines integrator will be available.

