SDL: Fix compilation (see #5313)

SDL Commits
1 
From 04256a537255875dd4ba136b3a00b5bd7d15edc6 Mon Sep 17 00:00:00 2001
From: Sylvain <[EMAIL REDACTED]>
Date: Wed, 9 Mar 2022 15:12:25 +0100
Subject: [PATCH] Fix compilation (see #5313)

---
 src/render/opengles2/SDL_render_gles2.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/render/opengles2/SDL_render_gles2.c b/src/render/opengles2/SDL_render_gles2.c
index d5af3e4eaab..c2f5d640f87 100644
--- a/src/render/opengles2/SDL_render_gles2.c
+++ b/src/render/opengles2/SDL_render_gles2.c
@@ -1379,6 +1379,7 @@ GLES2_CreateTexture(SDL_Renderer *renderer, SDL_Texture *texture)
         type = GL_UNSIGNED_BYTE;
         break;
 #endif
+#ifdef GL_TEXTURE_EXTERNAL_OES
     case SDL_PIXELFORMAT_EXTERNAL_OES:
         format = GL_NONE;
         type = GL_NONE;
@@ -2142,6 +2143,7 @@ GLES2_CreateRenderer(SDL_Window *window, Uint32 flags)
     renderer->info.texture_formats[renderer->info.num_texture_formats++] = SDL_PIXELFORMAT_NV12;
     renderer->info.texture_formats[renderer->info.num_texture_formats++] = SDL_PIXELFORMAT_NV21;
 #endif
+#ifdef GL_TEXTURE_EXTERNAL_OES
     renderer->info.texture_formats[renderer->info.num_texture_formats++] = SDL_PIXELFORMAT_EXTERNAL_OES;
 #endif