Getting TkAgg backend to work on OS X

I believe this is the right list, since the question deals with
compiling, rather than using, matplotlib. Hope that's OK.

I just dl'ed, and after setting the TkAgg flag to 1 in setup.py,
did a python setup.py install. (Note that I had done
a previous install without the TkAgg flag set.) On my system,
this is producing a bunch of errors related to the Tk headers:

...
running build_ext
building 'matplotlib.backends._tkagg' extension
creating build/temp.darwin-7.3.0-Power_Macintosh-2.3
creating build/temp.darwin-7.3.0-Power_Macintosh-2.3/src
gcc -fno-strict-aliasing -Wno-long-double -no-cpp-precomp -mno-fused-madd -fno-common -dynamic -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -I/usr/local/include -I/usr/local/include/freetype2 -Isrc -Iagg2/include -I/System/Library/Frameworks/Python.framework/Versions/2.3/include/python2.3 -c src/_tkagg.cpp -o build/temp.darwin-7.3.0-Power_Macintosh-2.3/src/_tkagg.o
In file included from src/_tkagg.cpp:18:
/Library/Frameworks/Tk.framework/Headers/tk.h:96:29: X11/Xlib.h: No such file or directory
In file included from src/_tkagg.cpp:18:
/Library/Frameworks/Tk.framework/Headers/tk.h:572: error: `Tk_ClassCreateProc'
    was not declared in this scope
/Library/Frameworks/Tk.framework/Headers/tk.h:573: error: type specifier
    omitted for parameter `Window'
/Library/Frameworks/Tk.framework/Headers/tk.h:573: error: parse error before `,
    ' token
/Library/Frameworks/Tk.framework/Headers/tk.h:573: error: typedef `Window' is
    initialized (use __typeof__ instead)
/Library/Frameworks/Tk.framework/Headers/tk.h:576: error: type specifier
    omitted for parameter `XEvent'
...

and so on, for a very long time.

I have done some messing around with Tk--I'm currently running AquaTcl/Tk, not the
X11 version--but don't have a good handle on how to deal with the above. Any
ideas? I'd really like to start using matplotlib!

Thanks,
Ken McDonald