sdl2-compat: minor warning fixes.

SDL Commits
1 
From 6207af8c7de2aa7c8cbccd3c6bddfc828ebf6282 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Sat, 24 Dec 2022 11:50:56 +0300
Subject: [PATCH] minor warning fixes.

---
 src/sdl2_compat.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/sdl2_compat.c b/src/sdl2_compat.c
index 0bed778..2cb7471 100644
--- a/src/sdl2_compat.c
+++ b/src/sdl2_compat.c
@@ -2764,12 +2764,12 @@ SDL_Has3DNow(void)
     if (SDL3_HasMMX()) {
         int a, b, c, d;
         cpuid(0x80000000, a, b, c, d);
-        if (a >= 0x80000001) {
+        if ((unsigned int)a >= 0x80000001) {
             cpuid(0x80000001, a, b, c, d);
-            return d & 0x80000000;
+            return (d & 0x80000000) ? SDL_TRUE : SDL_FALSE;
         }
     }
-    return 0;
+    return SDL_FALSE;
 }
 
 #ifdef __cplusplus