"make" problem compiling openbox 3.1:libobrender_la-font.lo

[Roberto Nicolini]

Hallo to the list, and thank you in advance for helping!

I'm trying to compile openbox 3.1 on Debian, and can't go beyond the "make".
I've installed all the required libraries as listed on the openbox website, 
apart from Startup-Notification, which is stated as "optional".
After ./configure ends, I give make, and get the following error

render/font.c: In function `font_measure_full':
render/font.c:146: parse error before "FcChar8"
render/font.c: In function `RrFontDraw':
render/font.c:237: `FcChar8' undeclared (first use in this function)
render/font.c:237: parse error before ')' token
render/font.c:247: parse error before ')' token
make[1]: *** [render/render_libobrender_la-font.lo] Error 1
make[1]: Leaving directory `/home/usul/Compile/openbox-3.1'
make: *** [all-recursive] Error 1

On Google I couldn't find any occurence of libobrender, or other helpful 
hints.
I've had a look in ~/Compile/openbox-3.1/render and did find a 
render_libobrender_la-font.loT, but no .lo.

Does anyone know where the problem may lay?

Thank you,
Roberto