SDL: BigEndian: fix code that generates illegal instruction with gcc-4.9.2 on powerpc

SDL Commits
1 
From 6101499c7c1254d26858724655c3d999c7c7f4d2 Mon Sep 17 00:00:00 2001
From: Sylvain <[EMAIL REDACTED]>
Date: Thu, 16 Dec 2021 09:07:31 +0100
Subject: [PATCH] BigEndian: fix code that generates illegal instruction with
 gcc-4.9.2 on powerpc

Program received signal SIGILL, Illegal instruction.
X11_InitKeyboard (_this=0x1001f8f0)
    at /home/sdl/SDL_git/src/video/x11/SDL_x11keyboard.c:273
273	    XKeyboardState values = { .global_auto_repeat = AutoRepeatModeOff };
---
 src/video/x11/SDL_x11keyboard.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/video/x11/SDL_x11keyboard.c b/src/video/x11/SDL_x11keyboard.c
index 2214ba3e3e1..5626da5b184 100644
--- a/src/video/x11/SDL_x11keyboard.c
+++ b/src/video/x11/SDL_x11keyboard.c
@@ -267,7 +267,9 @@ X11_InitKeyboard(_THIS)
     int best_index;
     int distance;
     Bool xkb_repeat = 0;
-    XKeyboardState values = { .global_auto_repeat = AutoRepeatModeOff };
+    XKeyboardState values;
+    SDL_zero(values);
+    values.global_auto_repeat = AutoRepeatModeOff;
     
     X11_XGetKeyboardControl(data->display, &values);
     if (values.global_auto_repeat != AutoRepeatModeOn)