"_self" is a said to be a reserved word in Watcom C 10.6.  I'm
not sure that's really standard compliant behaviour, but I guess
we have to fix that anyway...
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 3dd5c26..b8c7584 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -1476,7 +1476,7 @@
 }
 
 static PyObject*
-treebuilder(PyObject* _self, PyObject* args)
+treebuilder(PyObject* self_, PyObject* args)
 {
     if (!PyArg_ParseTuple(args, ":TreeBuilder"))
         return NULL;
@@ -2201,7 +2201,7 @@
 /* constructor and destructor */
 
 static PyObject*
-xmlparser(PyObject* _self, PyObject* args, PyObject* kw)
+xmlparser(PyObject* self_, PyObject* args, PyObject* kw)
 {
     XMLParserObject* self;
     /* FIXME: does this need to be static? */