Interestingly, Encode::Newlines does it as follows:

use constant Native => (
    ($^O =~ /^(?:MSWin|cygwin|dos|os2)/) ? CRLF :
    ($^O =~ /^MacOS/) ? CR : LF
);
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I guess that this, which some special handling for VMS where the line ending is set by file and EDBCDI systems where line endings are the lesser problem, should cover 99% of the cases.