I took a look at the rules file and i'm not sure what's causing the broken install, but there seems to be some weirdness with the optification. It seems that the .desktop file and icons are all put in /opt, which afaik isn't going to work as intended. Without comparing the previous rules to the present rules it's hard to say if any of the changes for optification are causing the break, but it's possible. There's actually one point where it looks like a file that shouldn't exist in that location is being moved during install, but i have rather poor comprehension as of yet in the arcane languages of make and its ilk.