It gets initialized when pyexpat is imported, and is only accessible as an
attribute of pyexpat; it cannot be imported itself. This allows it to at
least be importable after pyexpat itself has been imported by adding it
to sys.modules, so it is not quite as strange.
This arrangement needs to be better thought out.
For more comments, read the patches@python.org archives.
For documentation read the comments in mymalloc.h and objimpl.h.
(This is not exactly what Vladimir posted to the patches list; I've
made a few changes, and Vladimir sent me a fix in private email for a
problem that only occurs in debug mode. I'm also holding back on his
change to main.c, which seems unnecessary to me.)
The Setup.in entry is sort of a lie; it links with -lexpat, but
Expat's Makefile doesn't actually build a libexpat.a. I'll send
Expat's author a patch to do that; if he doesn't accept it, this
rule will have to list Expat's object files (ick!), or have a
comment explaining how to build a .a file.