message: cmake: assume FFTW threads are always enabled on Windows
diff: @@ -103,6 +103,12 @@ include( FindPackageHandleStandardArgs )
  FIND_PACKAGE_HANDLE_STANDARD_ARGS( FFTW
  REQUIRED_VARS FFTW_INCLUDE_DIRS FFTW_LIBRARIES )
  +# assume the threads feature is always enabled on Windows, since it's
  +# not a separate library there
  +if( FFTW_FOUND AND WIN32 )
  + set( FFTW_MULTITHREAD TRUE )
  +endif()
  +
  if( NOT FFTW_FOUND )
  message( STATUS "FindFFTW could not find all of the following fftw libraries" )
  message( STATUS "${FFTW_FIND_COMPONENTS}" )
  