SDL: include: Fix triggering of Clang's -Wexpansion-to-defined in SDL_endian.h

From b8da02e6efe7c6558d6d27ad41e724653279ebc3 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sat, 18 Sep 2021 10:44:32 -0400
Subject: [PATCH] include: Fix triggering of Clang's -Wexpansion-to-defined in
 SDL_endian.h

It doesn't like #if statements that uses a macro that uses defined(x).
---
 include/SDL_endian.h | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/include/SDL_endian.h b/include/SDL_endian.h
index db72928eff..ae8fc60e63 100644
--- a/include/SDL_endian.h
+++ b/include/SDL_endian.h
@@ -93,16 +93,22 @@ extern "C" {
  */
 
 /* various modern compilers may have builtin swap */
-#define HAS_BUILTIN_BSWAP16 (_SDL_HAS_BUILTIN(__builtin_bswap16)) || \
-    (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))
-#define HAS_BUILTIN_BSWAP32 (_SDL_HAS_BUILTIN(__builtin_bswap32)) || \
-    (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)))
-#define HAS_BUILTIN_BSWAP64 (_SDL_HAS_BUILTIN(__builtin_bswap64)) || \
-    (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)))
+#if defined(__GNUC__)
+#   define HAS_BUILTIN_BSWAP16 (_SDL_HAS_BUILTIN(__builtin_bswap16)) || \
+        (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))
+#   define HAS_BUILTIN_BSWAP32 (_SDL_HAS_BUILTIN(__builtin_bswap32)) || \
+        (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
+#   define HAS_BUILTIN_BSWAP64 (_SDL_HAS_BUILTIN(__builtin_bswap64)) || \
+        (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
 
-/* this one is broken */
-#define HAS_BROKEN_BSWAP (defined(__GNUC__) && \
-    (__GNUC__ == 2 && __GNUC_MINOR__ <= 95))
+    /* this one is broken */
+#   define HAS_BROKEN_BSWAP (__GNUC__ == 2 && __GNUC_MINOR__ <= 95)
+#else
+#   define HAS_BUILTIN_BSWAP16 0
+#   define HAS_BUILTIN_BSWAP32 0
+#   define HAS_BUILTIN_BSWAP64 0
+#   define HAS_BROKEN_BSWAP 0
+#endif
 
 #if HAS_BUILTIN_BSWAP16
 #define SDL_Swap16(x) __builtin_bswap16(x)