SDL: SDL_atomic.h: Update SDL_CPUPauseInstruction for Watcom. (#7157)

From 507fc462db1ede9f3ca2c581809a7f1492ac1ff5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ji=C5=99=C3=AD=20Mal=C3=A1k?= <[EMAIL REDACTED]>
Date: Thu, 26 Jan 2023 15:00:02 +0100
Subject: [PATCH] SDL_atomic.h: Update SDL_CPUPauseInstruction for Watcom.
 (#7157)

Appropriate CPU directive can be used in #pragma aux so that it is not
necessary to hardcode instruction bytes.
---
 include/SDL_atomic.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/SDL_atomic.h b/include/SDL_atomic.h
index 22ea0191a4b2..8273287f960d 100644
--- a/include/SDL_atomic.h
+++ b/include/SDL_atomic.h
@@ -249,9 +249,8 @@ typedef void (*SDL_KernelMemoryBarrierFunc)();
 #elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64))
     #define SDL_CPUPauseInstruction() __yield()
 #elif defined(__WATCOMC__) && defined(__386__)
-    /* watcom assembler rejects PAUSE if CPU < i686, and it refuses REP NOP as an invalid combination. Hardcode the bytes.  */
     extern __inline void SDL_CPUPauseInstruction(void);
-    #pragma aux SDL_CPUPauseInstruction = "db 0f3h,90h"
+    #pragma aux SDL_CPUPauseInstruction = ".686p" ".xmm2" "pause"
 #else
     #define SDL_CPUPauseInstruction()
 #endif