TODO-autotools

TODO list for conversion to autotools
-------------------------------------

- we deal with Fortran 90/Fortran 2003 <-> C calling conventions
  through the AC_FC_WRAPPERS autoconf macro and its FC_FUNC/FC_FUNC_
  preprocessor macros.  However, we either need to hide this in a
  non-public header, or document how packages using scafacos can
  make use of this.

- implement automatic Fortran module dependency tracking?

- Allow to optionally build without Fortran 2003 support.  Some
  cluster systems have proprietary connects with old MPI implementations
  that are not easily upgradeable to support all needed MPI.

- the test suite helpers (test/defs.in) should provide methods to
  extract simulation results and validate them, compare errors, etc.

- add method specific options to top-level configure (via empty AC_ARG_ENABLE)

- clean AX_FFTW3 macro: remove --with-fftw3-options?

- use axes_extra_prefixes macro?