Don't create PLT symbols that don't match filtering criteria

- instead of creating them, keeping them around, and then just not enabling
  breakpoints for them
diff --git a/options.h b/options.h
index 9cd0bfc..82b13c8 100644
--- a/options.h
+++ b/options.h
@@ -21,7 +21,7 @@
 #if defined(HAVE_LIBUNWIND)
 	int bt_depth;	 /* how may levels of stack frames to show */
 #endif /* defined(HAVE_LIBUNWIND) */
-	struct filter *filter;
+	struct filter *plt_filter;
 	int hide_caller; /* Whether caller library should be hidden.  */
 };
 extern struct options_t options;