[pygobject] fix a couple of compiler warnings

[Tomeu Vizoso <tomeuv src gnome org>]

commit 2da8da589644d6125101210712defb1272a8abb1
Author: John (J5) Palmieri <johnp redhat com>
Date:   Thu Sep 9 13:52:14 2010 -0400

    fix a couple of compiler warnings
    
    https://bugzilla.gnome.org/show_bug.cgi?id=629199

 gi/pygi-argument.c      |    4 ++--
 gi/pygi-struct.c        |    2 +-
 gobject/gobjectmodule.c |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/gi/pygi-argument.c b/gi/pygi-argument.c
index 82d5855..e3dd8c3 100644
--- a/gi/pygi-argument.c
+++ b/gi/pygi-argument.c
@@ -749,7 +749,7 @@ _pygi_argument_from_object (PyObject   *object,
         }
         case GI_TYPE_TAG_UTF8:
         {
-            const gchar *string;
+            gchar *string;
 
             if (object == Py_None) {
                 arg.v_string = NULL;
@@ -774,7 +774,7 @@ _pygi_argument_from_object (PyObject   *object,
         case GI_TYPE_TAG_FILENAME:
         {
             GError *error = NULL;
-            const gchar *string;
+            gchar *string;
 
 #if PY_VERSION_HEX < 0x03000000
             string = g_strdup(PyString_AsString (object));
diff --git a/gi/pygi-struct.c b/gi/pygi-struct.c
index caa0ffb..c2e1f4d 100644
--- a/gi/pygi-struct.c
+++ b/gi/pygi-struct.c
@@ -31,7 +31,7 @@ static void
 _struct_dealloc (PyGIStruct *self)
 {
     GIBaseInfo *info = _pygi_object_get_gi_info (
-                           Py_TYPE((PyObject *) self),
+                           (PyObject *) self,
                            &PyGIStructInfo_Type);
 
     PyObject_GC_UnTrack ( (PyObject *) self);
diff --git a/gobject/gobjectmodule.c b/gobject/gobjectmodule.c
index 804d5b0..4e9c07d 100644
--- a/gobject/gobjectmodule.c
+++ b/gobject/gobjectmodule.c
@@ -1192,7 +1192,7 @@ pyg_type_register(PyTypeObject *class, const char *type_name)
 
     /* set new value of __gtype__ on class */
     gtype = pyg_type_wrapper_new(instance_type);
-    PyObject_SetAttrString(class, "__gtype__", gtype);
+    PyObject_SetAttrString((PyObject *)class, "__gtype__", gtype);
     Py_DECREF(gtype);
 
       /* propagate new constructor API compatility flag from parent to child type */