(1) Use PyErr_NewException("module.class", NULL, NULL) to create the
exception object.
(2) Remove all calls to Py_FatalError(); instead, return or
ignore the errors -- the import code now checks PyErr_Occurred()
after calling a module's init function, so it's no longer a
fatal error for the initialization to fail.
Also did some small cleanups, e.g. removed unnecessary test for
"already initialized" from initfpectl(), and unified
initposix()/initnt().
I haven't checked this very thoroughly, so while the changes are
pretty trivial -- beware of untested code!
getpagesize() -- #ifdef doesn't work, Linux has conflicting decls in
its headers. Choice: only declare the return type, not the argument
prototype, and not on Linux.
