[gimp] app: in GimpBacktrace Linux backend, make blacklisted_thread_names const

[Ell <ell src gnome org>]

commit c749097dcc0f70f4986dd030980f9e1575a73b5f
Author: Ell <ell_se yahoo com>
Date:   Sat Dec 1 03:51:12 2018 -0500

    app: in GimpBacktrace Linux backend, make blacklisted_thread_names const

 app/core/gimpbacktrace-linux.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/core/gimpbacktrace-linux.c b/app/core/gimpbacktrace-linux.c
index 3d3c6afc0d..72a50db29d 100644
--- a/app/core/gimpbacktrace-linux.c
+++ b/app/core/gimpbacktrace-linux.c
@@ -119,7 +119,7 @@ static gint              handler_lock;
 static struct backtrace_state *backtrace_state;
 #endif
 
-static const gchar *blacklisted_thread_names[] =
+static const gchar * const blacklisted_thread_names[] =
 {
   "gmain",
   "threaded-ml"