fix mixing up of SDL and libc allocators, proper flushing of quad build buffers

src/rendering/twn_deferred_commands.h

@@ -43,7 +43,7 @@ typedef struct {
     TextureKey texture_key;
     GPUTexture gpu_texture;
 
-    /* could be either `element_count` with supplied `element_buffer`, or this, but not both */
+    /* could be either `element_count` with supplied `element_buffer`, or `primitive_count`, but not both */
     uint32_t primitive_count;
     uint32_t element_buffer;
     uint32_t element_count;