diff --git a/include/wx/unix/execute.h b/include/wx/unix/execute.h
index ef2869a512..7336597b1d 100644
--- a/include/wx/unix/execute.h
+++ b/include/wx/unix/execute.h
@@ -28,7 +28,10 @@ extern void wxHandleProcessTermination(wxEndProcessData *proc_data);
 // this function is called to associate the port-specific callback with the
 // child process. The return valus is port-specific.
 extern int wxAddProcessCallback(wxEndProcessData *proc_data, int fd);
+
+#if defined(__DARWIN__) && defined(__WXMAC__)
 // For ports (e.g. DARWIN) which can add callbacks based on the pid
 extern int wxAddProcessCallbackForPid(wxEndProcessData *proc_data, int pid);
+#endif
 
 #endif // _WX_UNIX_EXECUTE_H