diff --git a/ui/curses.c b/ui/curses.c
index 3a1b71451c..3bafc10c1c 100644
--- a/ui/curses.c
+++ b/ui/curses.c
@@ -529,7 +529,7 @@ static void font_setup(void)
      * Control characters are normally non-printable, but VGA does have
      * well-known glyphs for them.
      */
-    static uint16_t control_characters[0x20] = {
+    static const uint16_t control_characters[0x20] = {
       0x0020,
       0x263a,
       0x263b,