support for centos

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>
add centos support to __postfix* types

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>
ensure file exists

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>
support for centos

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>