diff --git a/code/sdl/sdl_input.c b/code/sdl/sdl_input.c
index dcd21439..9048d5b7 100644
--- a/code/sdl/sdl_input.c
+++ b/code/sdl/sdl_input.c
@@ -910,7 +910,7 @@ IN_InitKeyLockStates
 */
 void IN_InitKeyLockStates( void )
 {
-	unsigned char *keystate = SDL_GetKeyboardState(NULL);
+	const unsigned char *keystate = SDL_GetKeyboardState(NULL);
 
 	keys[K_SCROLLOCK].down = keystate[SDL_SCANCODE_SCROLLLOCK];
 	keys[K_KP_NUMLOCK].down = keystate[SDL_SCANCODE_NUMLOCKCLEAR];