[MITgcm-support] Build with nectdf

[Martin Losch]

Patti,

the build_options-files for genmake2 use bash-syntax. In bash, this "$NETCDF_ROOT" is different from '$NETCDF_ROOT' (the former expands NETCDF_ROOT, the latter doesn't); there are many resources online, that explain this in more detail. As a general rule I always use double quotes with bash, unless I want to pass variable names rather than their content.