Issue #2281 - Follow-up: Don't include headers in extern "C".

In C++17 mode using GCC 13 on Linux this is causing C linkage
to be applied to the throw_gcc.h functions instead of C++.

other-licenses/atk-1.0/atk/atkobject.h

@@ -20,14 +20,14 @@
 #ifndef __ATK_OBJECT_H__
 #define __ATK_OBJECT_H__
 
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-
 #include <glib-object.h>
 #include <atk/atkstate.h>
 #include <atk/atkrelationtype.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
 /*
  * AtkObject represents the minimum information all accessible objects
  * return. This information includes accessible name, accessible