https://bugs.gentoo.org/919213
Cast pointer as it is cast everywhere around it
--- a/gperiodic.c
+++ b/gperiodic.c
@@ -137,7 +137,7 @@
 	    if (col == 0) gtk_label_set_markup (GTK_LABEL (label), _(header.info[row]));
             else {
 	      gtk_label_set_markup (GTK_LABEL (label), _(entry->info[row]));
-	      gtk_label_set_selectable (label, TRUE);
+	      gtk_label_set_selectable (GTK_LABEL (label), TRUE);
 	    }
 
 	    gtk_misc_set_alignment(GTK_MISC(label), 0, 0);