Fixed bug 2908 - Fix clang warnings

Simon Deschenes

My build system still shows warning as errors.

The first warning says that the member named instances can never be false (or NULL) as it is a static array, and we should check for instances[index] which we do anyway.

src/render/opengles2/SDL_render_gles2.c

@@ -1030,9 +1030,6 @@ GLES2_CacheShader(SDL_Renderer *renderer, GLES2_ShaderType type, SDL_BlendMode b
     /* Find a matching shader instance that's supported on this hardware */
     for (i = 0; i < shader->instance_count && !instance; ++i) {
         for (j = 0; j < data->shader_format_count && !instance; ++j) {
-            if (!shader->instances) {
-                continue;
-            }
             if (!shader->instances[i]) {
                 continue;
             }