GCC: Get everything working with gcc 4.6.1.

And by "everything" I mean all the quick regressions.

src/python/m5/params.py

@@ -164,6 +164,7 @@ class ParamDesc(object):
         return self.ptype(value)
 
     def cxx_predecls(self, code):
+        code('#include <cstddef>')
         self.ptype.cxx_predecls(code)
 
     def swig_predecls(self, code):

src/python/swig/pyobject.cc

@@ -94,10 +94,6 @@ int
 connectPorts(SimObject *o1, const std::string &name1, int i1,
              SimObject *o2, const std::string &name2, int i2)
 {
-    MemObject *mo1, *mo2;
-    mo1 = dynamic_cast<MemObject*>(o1);
-    mo2 = dynamic_cast<MemObject*>(o2);
-
 #if FULL_SYSTEM
     EtherObject *eo1, *eo2;
     EtherDevice *ed1, *ed2;