man 5 hgrc implied you need to use external tools to do CRLF translation.
This is no longer true; win32text provides a much better in-process alternative.
#!/bin/sh
hg init dir
cd dir
echo bleh > bar
hg add bar
hg ci -m 'add bar'
hg cp bar foo
echo >> bar
hg ci -m 'cp bar foo; change bar'
hg debugrename foo
hg debugindex .hg/store/data/bar.i