support depth tex/stencil rb configs for g-buffer on intel


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1599 b412e182-2ed4-4078-95c4-27dc59f57fa9
intel depth-stencil tweaks


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1600 b412e182-2ed4-4078-95c4-27dc59f57fa9