New subroutine process_envxml_flags in CLMBuildNamelist.pm #3547
Description
Call the new subroutine from process_namelist_user_input.
So far this subroutine would just set cmip_era by taking this line
$nl_flags->{'cmip_era'} = $envxml_ref->{'CLM_CMIP_ERA'};
out of subroutine setup_cmdl_resolution.
Originally discussed in #3501 (comment)