Older classdesc releases, include fclassdesc, can be found under
EcoLab file releases (https://sourceforge.net/projects/ecolab/files/)
The latest release deliberately causes a linker failure if the mandatory
header file classdesc_epilogue.h is not included in your C++ source
file. If you have older code that generates this link failure, you
will need to add the appropriate #include line.