Excise DL_EXPORT from Include.

Thanks to Skip Montanaro and Kalle Svensson for the patches.
diff --git a/Include/cobject.h b/Include/cobject.h
index f710d4a..ccf8b32 100644
--- a/Include/cobject.h
+++ b/Include/cobject.h
@@ -14,7 +14,7 @@
 extern "C" {
 #endif
 
-extern DL_IMPORT(PyTypeObject) PyCObject_Type;
+PyAPI_DATA(PyTypeObject) PyCObject_Type;
 
 #define PyCObject_Check(op) ((op)->ob_type == &PyCObject_Type)
 
@@ -24,8 +24,8 @@
    destroyed.
 
 */
-extern DL_IMPORT(PyObject *)
-PyCObject_FromVoidPtr(void *cobj, void (*destruct)(void*));
+PyAPI_FUNC(PyObject *) PyCObject_FromVoidPtr(
+	void *cobj, void (*destruct)(void*));
 
 
 /* Create a PyCObject from a pointer to a C object, a description object,
@@ -33,21 +33,17 @@
    then it will be called with the first and second arguments if and when 
    the PyCObject is destroyed.
 */
-extern DL_IMPORT(PyObject *)
-PyCObject_FromVoidPtrAndDesc(void *cobj, void *desc,
-                             void (*destruct)(void*,void*));
+PyAPI_FUNC(PyObject *) PyCObject_FromVoidPtrAndDesc(
+	void *cobj, void *desc, void (*destruct)(void*,void*));
 
 /* Retrieve a pointer to a C object from a PyCObject. */
-extern DL_IMPORT(void *)
-PyCObject_AsVoidPtr(PyObject *);
+PyAPI_FUNC(void *) PyCObject_AsVoidPtr(PyObject *);
 
 /* Retrieve a pointer to a description object from a PyCObject. */
-extern DL_IMPORT(void *)
-PyCObject_GetDesc(PyObject *);
+PyAPI_FUNC(void *) PyCObject_GetDesc(PyObject *);
 
 /* Import a pointer to a C object from a module using a PyCObject. */
-extern DL_IMPORT(void *)
-PyCObject_Import(char *module_name, char *cobject_name);
+PyAPI_FUNC(void *) PyCObject_Import(char *module_name, char *cobject_name);
 
 #ifdef __cplusplus
 }