remove static FFTW library as strict dependency

CMakeLists.txt

@@ -103,6 +103,7 @@ else(MKL_FOUND)
     else(BUILD_STATIC)
       set(FFT_LIBRARIES "${FFTW3F_LIBRARIES}")
     endif(BUILD_STATIC)
+    message(STATUS "FFT_LIBRARIES: " ${FFT_LIBRARIES})
   endif(FFTW3F_FOUND)
 endif(MKL_FOUND)
 

cmake/modules/FindFFTW3F.cmake

@@ -39,6 +39,6 @@ include(FindPackageHandleStandardArgs)
 # handle the QUIETLY and REQUIRED arguments and set FFTW3F_FOUND to TRUE
 # if all listed variables are TRUE
 find_package_handle_standard_args(fftw3f  DEFAULT_MSG
-                                  FFTW3F_LIBRARY FFTW3F_STATIC_LIBRARY FFTW3F_INCLUDE_DIR)
+                                  FFTW3F_LIBRARY FFTW3F_INCLUDE_DIR)
 
 mark_as_advanced(FFTW3F_INCLUDE_DIR FFTW3F_STATIC_LIBRARY FFTW3F_LIBRARY )