Probe Apple GL extensions at runtime instead of assuming them on macOS.

A macOS build of the GL renderer can run against a non-Apple GL - Mesa
via the Wayland video driver, or Mesa GLX in a Cocoa-less X11 build -
where GL_APPLE_ycbcr_422, GL_APPLE_texture_range and
GL_APPLE_client_storage do not exist. Advertising UYVY unconditionally
made ffplay/mpv negotiate a texture format whose glTexImage2D then
failed with GL_INVALID_ENUM, leaving the window empty; the storage-hint
glTexParameteri calls raised the same error on every texture. Gate all
three paths on the extension string; Apple's own GL always advertises
them, so CGL behavior is unchanged.

--- src/render/opengl/SDL_render_gl.c
+++ src/render/opengl/SDL_render_gl.c
@@ -109,6 +109,14 @@ typedef struct
     bool GL_EXT_framebuffer_object_supported;
     GL_FBOList *framebuffers;
 
+#ifdef SDL_PLATFORM_MACOS
+    /* A macOS build may run against a non-Apple GL, e.g. Mesa via the
+       Wayland video driver, which lacks the Apple extensions. */
+    bool GL_APPLE_ycbcr_422_supported;
+    bool GL_APPLE_texture_range_supported;
+    bool GL_APPLE_client_storage_supported;
+#endif
+
     // OpenGL functions
 #define SDL_PROC(ret, func, params) ret (APIENTRY *func) params;
 #include "SDL_glfuncs.h"
@@ -417,7 +425,7 @@ static bool GL_SupportsBlendMode(SDL_Renderer *renderer, SDL_BlendMode blendMode
     return true;
 }
 
-static bool convert_format(Uint32 pixel_format, GLint *internalFormat, GLenum *format, GLenum *type)
+static bool convert_format(GL_RenderData *renderdata, Uint32 pixel_format, GLint *internalFormat, GLenum *format, GLenum *type)
 {
     switch (pixel_format) {
     case SDL_PIXELFORMAT_BGRA32:
@@ -443,6 +451,9 @@ static bool convert_format(Uint32 pixel_format, GLint *internalFormat, GLenum *f
         break;
 #ifdef SDL_PLATFORM_MACOS
     case SDL_PIXELFORMAT_UYVY:
+        if (!renderdata->GL_APPLE_ycbcr_422_supported) {
+            return false;
+        }
         *internalFormat = GL_RGB8;
         *format = GL_YCBCR_422_APPLE;
         *type = GL_UNSIGNED_SHORT_8_8_APPLE;
@@ -574,7 +585,7 @@ static bool GL_CreateTexture(SDL_Renderer *renderer, SDL_Texture *texture, SDL_P
         return SDL_SetError("Render targets not supported by OpenGL");
     }
 
-    if (!convert_format(texture->format, &internalFormat, &format, &type)) {
+    if (!convert_format(renderdata, texture->format, &internalFormat, &format, &type)) {
         return SDL_SetError("Texture format %s not supported by OpenGL",
                             SDL_GetPixelFormatName(texture->format));
     }
@@ -664,14 +675,17 @@ static bool GL_CreateTexture(SDL_Renderer *renderer, SDL_Texture *texture, SDL_P
 #ifndef STORAGE_SHARED_APPLE
 #define STORAGE_SHARED_APPLE 0x85BF
 #endif
-    if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
-        renderdata->glTexParameteri(textype, GL_TEXTURE_STORAGE_HINT_APPLE,
-                                    GL_STORAGE_SHARED_APPLE);
-    } else {
-        renderdata->glTexParameteri(textype, GL_TEXTURE_STORAGE_HINT_APPLE,
-                                    GL_STORAGE_CACHED_APPLE);
+    if (renderdata->GL_APPLE_texture_range_supported) {
+        if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
+            renderdata->glTexParameteri(textype, GL_TEXTURE_STORAGE_HINT_APPLE,
+                                        GL_STORAGE_SHARED_APPLE);
+        } else {
+            renderdata->glTexParameteri(textype, GL_TEXTURE_STORAGE_HINT_APPLE,
+                                        GL_STORAGE_CACHED_APPLE);
+        }
     }
-    if (texture->access == SDL_TEXTUREACCESS_STREAMING && texture->format == SDL_PIXELFORMAT_ARGB8888 && (texture->w % 8) == 0) {
+    if (renderdata->GL_APPLE_client_storage_supported &&
+        texture->access == SDL_TEXTUREACCESS_STREAMING && texture->format == SDL_PIXELFORMAT_ARGB8888 && (texture->w % 8) == 0) {
         renderdata->glPixelStorei(GL_UNPACK_CLIENT_STORAGE_APPLE, GL_TRUE);
         renderdata->glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
         renderdata->glPixelStorei(GL_UNPACK_ROW_LENGTH,
@@ -1625,7 +1639,7 @@ static SDL_Surface *GL_RenderReadPixels(SDL_Renderer *renderer, const SDL_Rect *
 
     GL_ActivateRenderer(renderer);
 
-    if (!convert_format(format, &internalFormat, &targetFormat, &type)) {
+    if (!convert_format(data, format, &internalFormat, &targetFormat, &type)) {
         SDL_SetError("Texture format %s not supported by OpenGL", SDL_GetPixelFormatName(format));
         return NULL;
     }
@@ -1994,7 +2008,12 @@ static bool GL_CreateRenderer(SDL_Renderer *renderer, SDL_Window *window, SDL_Pr
     }
 #endif
 #ifdef SDL_PLATFORM_MACOS
-    SDL_AddSupportedTextureFormat(renderer, SDL_PIXELFORMAT_UYVY);
+    data->GL_APPLE_ycbcr_422_supported = SDL_GL_ExtensionSupported("GL_APPLE_ycbcr_422");
+    data->GL_APPLE_texture_range_supported = SDL_GL_ExtensionSupported("GL_APPLE_texture_range");
+    data->GL_APPLE_client_storage_supported = SDL_GL_ExtensionSupported("GL_APPLE_client_storage");
+    if (data->GL_APPLE_ycbcr_422_supported) {
+        SDL_AddSupportedTextureFormat(renderer, SDL_PIXELFORMAT_UYVY);
+    }
 #endif
 
     if (SDL_GL_ExtensionSupported("GL_EXT_framebuffer_object")) {