Debian, TkAgg, can't find "tk.h"

When compiling matplotlib on debian with :
python setup.py install --home=/home/jonas/python

I get an error message about not being able to find tk.h (appended
below). This is with (I believe) all necessary tk libraries installed.
When I set CPATH=/usr/include/tcl8.4 and then try, it compiles just
fine. Is there any way we could make the tk-finding code a bit smarter
so it would work out of the box on debian?

Thanks for such an amazing plotting package -- at last, I might be able
to ditch matlab!
    ...Eric

[full error below]

running install
running build
running build_py
running build_ext
building 'matplotlib.backends._tkagg' extension
gcc -pthread -fno-strict-aliasing -DNDEBUG -g -O3 -Wall
-Wstrict-prototypes -fPI
C -I/usr/lib/tcl8.4/../../include -I/usr/include -Isrc -Iagg2/include
-I/usr/inc
lude -I/usr/lib/tcl8.4/../../include/freetype2 -I/usr/include/freetype2
-Isrc/fr
eetype2 -Iagg2/include/freetype2 -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:20:19: tk.h: No such file or directory
src/_tkagg.cpp:28: error: syntax error before `*' token
src/_tkagg.cpp:32: error: `ClientData' was not declared in this scope
src/_tkagg.cpp:32: error: parse error before `,' token
src/_tkagg.cpp: In function `int PyAggImagePhoto(...)':
src/_tkagg.cpp:35: error: `Tk_PhotoHandle' undeclared (first use this
function)
src/_tkagg.cpp:35: error: (Each undeclared identifier is reported only
once for
   each function it appears in.)
src/_tkagg.cpp:35: error: parse error before `;' token
src/_tkagg.cpp:36: error: `Tk_PhotoImageBlock' undeclared (first use
this
   function)
src/_tkagg.cpp:40: error: `argc' undeclared (first use this function)
src/_tkagg.cpp:41: error: `interp' undeclared (first use this function)
src/_tkagg.cpp:41: error: `argv' undeclared (first use this function)
src/_tkagg.cpp:42: error: `Tcl_AppendResult' undeclared (first use this
   function)
src/_tkagg.cpp:43: error: `TCL_ERROR' undeclared (first use this
function)
src/_tkagg.cpp:47: error: `photo' undeclared (first use this function)
src/_tkagg.cpp:47: error: `Tk_FindPhoto' undeclared (first use this
function)
src/_tkagg.cpp:65: error: `block' undeclared (first use this function)
src/_tkagg.cpp:88: error: `Tk_PhotoBlank' undeclared (first use this
function)
src/_tkagg.cpp:90: error: `Tk_PhotoPutBlock' undeclared (first use this
   function)
src/_tkagg.cpp:92: error: `TCL_OK' undeclared (first use this function)
src/_tkagg.cpp: In function `PyObject* _tkinit(PyObject*, PyObject*)':
src/_tkagg.cpp:108: error: `Tcl_Interp' undeclared (first use this
function)
src/_tkagg.cpp:117: error: parse error before `)' token
src/_tkagg.cpp:122: error: 'struct TkappObject' has no member named
'interp'
src/_tkagg.cpp:128: error: `Tcl_CmdProc' undeclared (first use this
function)
src/_tkagg.cpp:128: error: parse error before `)' token
error: command 'gcc' failed with exit status 1