wxPython build cannot find include files

I have a PC with an AMD64 chip and up-to-date Debian unstable ("i386"
version). I prefer to compile Python related programs myself. They are all
kept in "/usr/local".

I downloaded wxPython and expanded the tarball. In
/usr/local/src/wxPython-src-2.6.2.1, I executed my version of "./.configure"
which is:

cd build
../configure --prefix=/usr/local \
             --with-gtk \
             --with-gnomeprint \
             --with-opengl \
             --enable-optimize \
             --enable-geometry \
             --enable-mediactrl \
             --enable-display \
             --disable-debugreport \
             --enable-debug_flag \
             --enable-unicode

Then I executed "./.make" which is;

cd build
make $* \
    && make -C contrib/src/animate $* \
    && make -C contrib/src/gizmos $* \
    && make -C contrib/src/stc $*

Then I ran "./.make install". "wxWidgets" seemed to install correctly. The
install put a symbolic link to "wx-config" in "/usr/local/bin". The include
files were put in "/usr/local/include/wx-2.6/wx". A directory
"/usr/local/lib/wx" was created. It contains
"/usr/local/lib/wx/config/gtk2-unicode-debug-2.6" and
"/usr/local/lib/wx/include/gtk2-unicode-debug-2.6/wx/setup.h".

Note the location of the includes in the source:
"/usr/local/src/wxPython-src-2.6.2.1/include/wx".

···

====
I changed directory to "wxPython".

At the command line I did:

    UNICODE=1
    python setup.py build_ext --inplace --debug

Several copies of a warning were printed:

  Warning: No config found to match: /usr/local/bin/wx-config --toolkit=gtk2
  --unicode=no --version=2.6 --cxxflags
           in /usr/local/lib/wx/config
  If you require this configuration, please install the desired
  library build. If this is part of an automated configuration
  test and no other errors occur, you may safely ignore it.
  You may use wx-config --list to see all configs available in
  the default prefix.
...
Found wx-config: /usr/local/bin/wx-config
    Using flags: --toolkit=gtk2 --unicode=no --version=2.6
Preparing CORE...
Preparing GLCANVAS...
Preparing STC...
Preparing GIZMOS...
Preparing ANIMATE...
running build_ext
building '_core_' extension
gcc -pthread -fno-strict-aliasing -DNDEBUG -g -O3 -Wall -Wstrict-prototypes
-fPIC -g -DSWIG_TYPE_TABLE=_wxPython_table -DHAVE_CONFIG_H
-DWXP_USE_THREAD=1 -UNDEBUG -DXTHREADS -Iinclude -Isrc
-I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include -I/usr/include/atk-1.0
-I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/X11R6/include
-I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include
-I/usr/local/include/python2.4 -c src/helpers.cpp -o
build-gtk2/temp.linux-i686-2.4/src/helpers.o -g -O0
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for
Ada/C/ObjC but not for C++
In file included from src/helpers.cpp:16:
include/wx/wxPython/wxPython_int.h:19:19: error: wx/wx.h: No such file or
directory
...

How do I fix this mess? Where are the definitive install instructions for
wxPython 2.6.2.1?