Fixed FreeBSD build

(cherry picked from commit a4c6b38fef2ff046e38072200b096c03389bfa28)

src/core/freebsd/SDL_evdev_kbd_freebsd.c

@@ -468,6 +468,10 @@ static void k_shift(SDL_EVDEV_keyboard_state *kbd, unsigned char value, char up_
     }
 }
 
+void SDL_EVDEV_kbd_set_muted(SDL_EVDEV_keyboard_state *state, SDL_bool muted)
+{
+}
+
 void SDL_EVDEV_kbd_keycode(SDL_EVDEV_keyboard_state *kbd, unsigned int keycode, int down)
 {
     keymap_t key_map;

src/core/linux/SDL_evdev_kbd.c

@@ -830,6 +830,7 @@ SDL_EVDEV_keyboard_state *SDL_EVDEV_kbd_init(void)
 void SDL_EVDEV_kbd_set_muted(SDL_EVDEV_keyboard_state *state, SDL_bool muted)
 {
 }
+
 void SDL_EVDEV_kbd_keycode(SDL_EVDEV_keyboard_state *state, unsigned int keycode, int down)
 {
 }