Strange build error (Xlib related)

[Seth Delackner <seth at jtan dot com>]

I've searched the whole mailing list and found no answer (nor in the FAQ):

I am trying to build 'bbkeys' which depends on some standard Xlib stuff, but it dies on the following final make step:

c++  -O2 -Wall  -I/usr/X11R6/include -s  -L/usr/X11R6/lib  -lSM -lICE -lX11  -o bbkeys  bbkeys.o Image.o LinkedList.o Timer.o stackmenu.o main.o resource.o Baseresource.o Basewindow.o BaseDisplay.o Basemenu.o wminterface.o NETInterface.o -L/usr/X11R6/lib 
bbkeys.o(.text+0xfc):bbkeys.cc: undefined reference to `XGetModifierMapping'
[followed by MANY more undefined references]

I just installed the current 4.1 X build by following all the steps in the users guide, and I verified that /usr/X11R6/{lib|include} have the Xlib files where these undefined items are...

If anyone wants to give it a shot, the source is at http://movingparts.thelinuxcommunity.org/bbkeys/bbkeys-0.8.2.tar.gz

I'm really just trying to find some WM that lets me assign something other than "Alt-Tab" to cycle windows, since Alt-Tab is stuck jumping out of X.