It took me a while to get Python 2.1.1's pyexpat module to build on my laptop, which runs Debian 2.2, also known as "potato". Eventually, I figured out how to do it. After running "./configure" in the Python211 directory, but before running "make", I edited Python211/Modules/Setup to include the following line:
pyexpat pyexpat.c -I/usr/include/xmltok -lxmltok -lxmlparse
I had to install the libxmltok1-dev Debian package to get the header files and libraries this links with.