gtk_combo_box_get_active_text didn't appear until GTK 2.6; bodge

around it for earlier versions of GTK 2.

[originally from svn r7969]

unix/gtkdlg.c

@@ -368,7 +368,12 @@ void dlg_editbox_get(union control *ctrl, void *dlg, char *buffer, int length)
     } else {
 	assert(uc->combo != NULL);
 	strncpy(buffer,
+#if GTK_CHECK_VERSION(2,6,0)
 		gtk_combo_box_get_active_text(GTK_COMBO_BOX(uc->combo)),
+#else
+		gtk_entry_get_text
+		(GTK_ENTRY(gtk_bin_get_child(GTK_BIN(uc->combo)))),
+#endif
 		length);
 	buffer[length-1] = '\0';
     }