SNNS Lives!
One of the main reasons I had been exploring Lens was because my previous faithful neural network simulator, SNNS, hadn't seen any development for years and one of the features necessary for SOM's was not working. In particular, the editor windows accessible through the control window had a display issue that rendered them useless.
Today however, I discovered the snns-dev project where further development of SNNS has been occurring. In fact, in 2004 the project group released a patch for the SNNS source that not only solves all the compile issues I discussed here, but also fixes the display issue that forced me to leave SNNS in the first place. As a bonus, a sneaky random number generator issue on Cygwin has also been addressed.
The patch applied smoothly to the SNNS v4.2 source and the configure and make process proceeded without errors. As promised, the display issues have also been fixed. SNNS lives!