[Rd] DIY Rtools?

[kaveh]

Dear List,

I'm currently working on an R package that
works great when compiled with GCC 4.8 under linux
but which doesn't seem to work so well when compiled
  by the win builder (http://win-builder.r-project.org/).

After asking around a bit, the primary culprit could be
the older version of GCC used in Rtools.

Now, for academic purposes, I would like to have
  a zip version of this package (not to distribute
through CRAN mind you, but to submit alongside
  the associated paper).

My questions are as follows:

-Am I correct to think that Rtool uses GCC 4.6.3?
-If so, is there a way to build windows runable R
package using a more recent version of GCC?

Thanks in advance for sharing your views on this,

Bests regards,