src/action_show_instance.c: Fix compiler warning.

diff --git a/src/action_show_instance.c b/src/action_show_instance.c
index 1fdef2f..7bf2fe8 100644 (file)
--- a/src/action_show_instance.c
+++ b/src/action_show_instance.c
@@ -381,7 +381,7 @@ int action_show_instance (void) /* {{{ */
 
   char tmp[128];
   char title[128];
-  char *format;
+  const char *format;
 
   memset (&pg_data, 0, sizeof (pg_data));
   pg_data.cfg = gl_graph_get_selected ();