xffm - error: secondary.h: No such file or directory

[Foxy]

I've got the following error compiling xffm-gui:

>  then mv -f ".deps/xffm_iconview-mcs-manager.Tpo" 
> ".deps/xffm_iconview-mcs-manager.Po"; else rm -f 
> ".deps/xffm_iconview-mcs-manager.Tpo"; exit 1; fi
> In file included from mcs-manager.c:45:
> /usr/include/xffm/xffm.h:4:23: error: secondary.h: No such file or 
> directory
> make[2]: *** [xffm_iconview-mcs-manager.o] Error 1
what is that secondary.h and why it cannot find it?