Log Message:
Changes 3.2.1:
* Performance improvements for some multidimensional r2c/c2r transforms;
  thanks to Eugene Miloslavsky for his benchmark reports.
* Compile with icc on MacOS X, use better icc compiler flags.
* Compilation fixes for systems where snprintf is defined as a macro;
  thanks to Marcus Mae for the bug report.
* Fortran documentation now recommends not using dfftw_execute,
  because of reports of problems with various Fortran compilers;
  it is better to use dfftw_execute_dft etcetera.
* Some documentation clarifications, e.g. of fact that --enable-openmp
  and --enable-threads are mutually exclusive (thanks to Long To),
  and document slightly odd behavior of plan_guru_r2r in Fortran.
* FAQ was accidentally omitted from 3.2 tarball.
* Remove some extraneous (harmless) files accidentally included in
  a subdirectory of the 3.2 tarball.