kchmviewer - configure failure: conditional "include_x11" was never defined.

All,

I ran into a configure failure regarding the conditional "include_x11":

chmlib to link : system checking if lib should be compiled... yes checking if po should be compiled... yes checking if src should be compiled... yes configure: error: conditional "include_x11" was never defined. Usually this means the macro was only invoked conditionally.

Is this a failure of the build script to include a necessary file or is this a failure of the configure code? I haven't run into a "conditional never defined" error with TDE before. What say the experts?

More importantly, how to fix it? All includes are in /usr/include/X11 - a pretty standard location.