fixes for support R build
fixing silo and mpi errors

git-svn-id: svn+ssh://portal-auth.nersc.gov/project/projectdirs/visit/svn/visit/trunk/src@21059 18c085ea-50e0-402c-830e-de6fd14e8384
Merge branch 'fix_vtk_definitions_and_r_support'

git-svn-id: svn+ssh://portal-auth.nersc.gov/project/projectdirs/visit/svn/visit/trunk/src@21060 18c085ea-50e0-402c-830e-de6fd14e8384