SDL: Handle the KMOD_SCROLL modifier on RISC OS

SDL Commits
1 
From 53b3db0c5d04ab97dbbcdc59321d0cd3258966ce Mon Sep 17 00:00:00 2001
From: Cameron Cawley <[EMAIL REDACTED]>
Date: Tue, 28 Sep 2021 17:59:16 +0100
Subject: [PATCH] Handle the KMOD_SCROLL modifier on RISC OS

---
 src/video/riscos/SDL_riscosevents.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/video/riscos/SDL_riscosevents.c b/src/video/riscos/SDL_riscosevents.c
index 3dbc3d0dc4..c527d0ff24 100644
--- a/src/video/riscos/SDL_riscosevents.c
+++ b/src/video/riscos/SDL_riscosevents.c
@@ -156,8 +156,9 @@ RISCOS_InitEvents(_THIS)
         driverdata->key_pressed[i] = 255;
 
     status = (_kernel_osbyte(202, 0, 255) & 0xFF);
-    SDL_ToggleModState(KMOD_NUM,  (status & (1 << 2)) == 0);
-    SDL_ToggleModState(KMOD_CAPS, (status & (1 << 4)) == 0);
+    SDL_ToggleModState(KMOD_NUM,    (status & (1 << 2)) == 0);
+    SDL_ToggleModState(KMOD_CAPS,   (status & (1 << 4)) == 0);
+    SDL_ToggleModState(KMOD_SCROLL, (status & (1 << 1)) != 0);
 
     /* Disable escape. */
     _kernel_osbyte(229, 1, 0);