Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
_CLEANUP_FUNC(GtkStackPage, g_object_unref)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/glib-2.0/glib/gmacros.h:1338:43: error: redefinition of âglib_autoptr_cleanup_GtkStackPageâ
 1338 | #defin
Information about an attempt to redefine a previously defined variable.