Move endian pixel format aliases into enum

Matches the same thing in `SDL_AudioFormat`.

include/SDL3/SDL_pixels.h

@@ -389,30 +389,30 @@ typedef enum SDL_PixelFormat
         /* SDL_DEFINE_PIXELFOURCC('N', 'V', '2', '1'), */
     SDL_PIXELFORMAT_P010 = 0x30313050u,      /**< Planar mode: Y + U/V interleaved  (2 planes) */
         /* SDL_DEFINE_PIXELFOURCC('P', '0', '1', '0'), */
-    SDL_PIXELFORMAT_EXTERNAL_OES = 0x2053454fu      /**< Android video texture format */
+    SDL_PIXELFORMAT_EXTERNAL_OES = 0x2053454fu,     /**< Android video texture format */
         /* SDL_DEFINE_PIXELFOURCC('O', 'E', 'S', ' ') */
-} SDL_PixelFormat;
 
-/* Aliases for RGBA byte arrays of color data, for the current platform */
-#if SDL_BYTEORDER == SDL_BIG_ENDIAN
-#define SDL_PIXELFORMAT_RGBA32 SDL_PIXELFORMAT_RGBA8888
-#define SDL_PIXELFORMAT_ARGB32 SDL_PIXELFORMAT_ARGB8888
-#define SDL_PIXELFORMAT_BGRA32 SDL_PIXELFORMAT_BGRA8888
-#define SDL_PIXELFORMAT_ABGR32 SDL_PIXELFORMAT_ABGR8888
-#define SDL_PIXELFORMAT_RGBX32 SDL_PIXELFORMAT_RGBX8888
-#define SDL_PIXELFORMAT_XRGB32 SDL_PIXELFORMAT_XRGB8888
-#define SDL_PIXELFORMAT_BGRX32 SDL_PIXELFORMAT_BGRX8888
-#define SDL_PIXELFORMAT_XBGR32 SDL_PIXELFORMAT_XBGR8888
-#else
-#define SDL_PIXELFORMAT_RGBA32 SDL_PIXELFORMAT_ABGR8888
-#define SDL_PIXELFORMAT_ARGB32 SDL_PIXELFORMAT_BGRA8888
-#define SDL_PIXELFORMAT_BGRA32 SDL_PIXELFORMAT_ARGB8888
-#define SDL_PIXELFORMAT_ABGR32 SDL_PIXELFORMAT_RGBA8888
-#define SDL_PIXELFORMAT_RGBX32 SDL_PIXELFORMAT_XBGR8888
-#define SDL_PIXELFORMAT_XRGB32 SDL_PIXELFORMAT_BGRX8888
-#define SDL_PIXELFORMAT_BGRX32 SDL_PIXELFORMAT_XRGB8888
-#define SDL_PIXELFORMAT_XBGR32 SDL_PIXELFORMAT_RGBX8888
-#endif
+    /* Aliases for RGBA byte arrays of color data, for the current platform */
+    #if SDL_BYTEORDER == SDL_BIG_ENDIAN
+    SDL_PIXELFORMAT_RGBA32 = SDL_PIXELFORMAT_RGBA8888,
+    SDL_PIXELFORMAT_ARGB32 = SDL_PIXELFORMAT_ARGB8888,
+    SDL_PIXELFORMAT_BGRA32 = SDL_PIXELFORMAT_BGRA8888,
+    SDL_PIXELFORMAT_ABGR32 = SDL_PIXELFORMAT_ABGR8888,
+    SDL_PIXELFORMAT_RGBX32 = SDL_PIXELFORMAT_RGBX8888,
+    SDL_PIXELFORMAT_XRGB32 = SDL_PIXELFORMAT_XRGB8888,
+    SDL_PIXELFORMAT_BGRX32 = SDL_PIXELFORMAT_BGRX8888,
+    SDL_PIXELFORMAT_XBGR32 = SDL_PIXELFORMAT_XBGR8888
+    #else
+    SDL_PIXELFORMAT_RGBA32 = SDL_PIXELFORMAT_ABGR8888,
+    SDL_PIXELFORMAT_ARGB32 = SDL_PIXELFORMAT_BGRA8888,
+    SDL_PIXELFORMAT_BGRA32 = SDL_PIXELFORMAT_ARGB8888,
+    SDL_PIXELFORMAT_ABGR32 = SDL_PIXELFORMAT_RGBA8888,
+    SDL_PIXELFORMAT_RGBX32 = SDL_PIXELFORMAT_XBGR8888,
+    SDL_PIXELFORMAT_XRGB32 = SDL_PIXELFORMAT_BGRX8888,
+    SDL_PIXELFORMAT_BGRX32 = SDL_PIXELFORMAT_XRGB8888,
+    SDL_PIXELFORMAT_XBGR32 = SDL_PIXELFORMAT_RGBX8888
+    #endif
+} SDL_PixelFormat;
 
 /**
  * Pixels are a representation of a color in a particular color space.