Check standard error code return values as < 0 instead of == -1

test/testime.c

@@ -361,7 +361,7 @@ static int unifont_load_texture(Uint32 textureID)
         }
         unifontTexture[UNIFONT_NUM_TEXTURES * i + textureID] = tex;
         SDL_SetTextureBlendMode(tex, SDL_BLENDMODE_BLEND);
-        if (SDL_UpdateTexture(tex, NULL, textureRGBA, UNIFONT_TEXTURE_PITCH) != 0) {
+        if (SDL_UpdateTexture(tex, NULL, textureRGBA, UNIFONT_TEXTURE_PITCH) < 0) {
             SDL_Log("unifont error: Failed to update texture %" SDL_PRIu32 " data for renderer %d.\n", textureID, i);
         }
     }