[matplotlib-devel] _tkagg build error

I'm trying to build from cvs.  It builds fine unless I try to build TkAgg:

------------------------
building 'matplotlib.backends._tkagg' extension
gcc -pthread -fno-strict-aliasing -DNDEBUG -O2 -fomit-frame-pointer -pipe 
-march=i586 -mcpu=pentiumpro -g -fPIC -I/usr/lib/tcl8.4/../../include 
-I/usr/include -Isrc -Iagg2/include -I/usr/include -I/usr/include/freetype2 
-I/usr/include/python2.3 -c src/_tkagg.cpp -o 
build/temp.linux-i686-2.3/src/_tkagg.o
src/_tkagg.cpp: In function `PyObject* _tkinit(PyObject*, PyObject*)':
src/_tkagg.cpp:134: error: invalid conversion from `int (*)(void*, 
Tcl_Interp*, int, char**)' to `int (*)(void*, Tcl_Interp*, int, const 
char**)'
error: command 'gcc' failed with exit status 1
-------------------------

I'm on Mandrake 10.0 which uses gcc 3.3.2
I apologize if I've made some obvious omission.
I'm no c wizard (that's why I want matplotlib!).

-gary