Move more specific help text to correct if branch.  Noticed by Karl in code review.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rprotobuf@737 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
adding some windows stuff

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rprotobuf@738 edb9625f-4e0d-4859-8d74-9fd3b1da38cb