BUG: inconsistency in fftw make (closes #14)

- fftw uses the double-precision interface only and thus
  makeFFTW should not have any special single-precision treatment.

- Bug is not apparent if the fftw was previously build with
  double-precision.

makeFFTW

@@ -128,17 +128,6 @@ else
     echo
 
     (
-        # configuration options:
-        unset configOpt
-
-        # Single-precision needed?
-        if [ "${WM_PRECISION_OPTION}" = SP ]
-        then
-            configOpt="$configOpt --enable-single"
-        fi
-
-        # end of configuration options
-        # ----------------------------
         buildDIR=$buildBASE/$fftwPACKAGE
 
         cd $FFTW_SOURCE_DIR || exit 1
@@ -154,7 +143,6 @@ else
             --libdir=$FFTW_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH \
             --enable-shared --disable-static \
             --disable-fortran \
-            $configOpt \
             && make -j $WM_NCOMPPROCS \
             && make install \
             && echo "Built $fftwPACKAGE"