Issues building testgtk on Debian Lenny/Sid

I'm learning GtkAda at the moment and currently I'm looking to build
testgtk. I've gotten through the compilation and binding stages, but
now on link I get the following:

gnatbind -aI/usr/share/ada/adainclude/gtkada2 -aO/usr/lib/adalib/
gtkada2 -I- -x /home/deadlyhead/temp/sources/GtkAda/testgtk/obj/
gnatlink /home/deadlyhead/temp/sources/GtkAda/testgtk/obj/testgtk.ali -
L/usr/lib -lgtkada2 -lgtk-x11-2.0 -lgdk-x11-2.0 -latk-1.0 -
lgdk_pixbuf-2.0 -lm -lpangocairo-1.0 -lfontconfig -lXext -lXrender -
lXinerama -lXi -lXrandr -lXcursor -lXfixes -lpango-1.0 -lcairo -lX11 -
lgobject-2.0 -lgmodule-2.0 -ldl -lglib-2.0 -o /home/deadlyhead/temp/
/usr/bin/ld: cannot find -lgtkada_gl
collect2: ld returned 1 exit status
gnatlink: error when calling /usr/bin/gcc-4.3
gnatmake: *** link failed.

I feel like this should be dead simple, but honestly, I've never fully
understood how ld works. In /usr/lib, I have both
2.12.0 and libgtkada_gl.a, plus all of the symlinks one would expect,
but ld just will not pick up on them. I've run ldconfig and
everything, but the error persists. I must be missing something here,
but I'm at a loss.

I'm currently using libgtkada2.12 from Debian Sid, with all of the
necessary libraries such as the mesa libs and libgtkada_gl2.12.
Everything that has a -dev package has had it installed. What could I
be missing?