Interesting. I’ve just tried to ./configure fvwm-themes against Fvwm-2.5.12, and it works fine.
Did you download the fvwm-themes-0.70 packaqe from http://fvwm-themes.sf.net ? Or are you using the one supplied wby your OS? I suggest downloading it from the main fvwm-themes site and trying again.
– Thomas Adam