add util.samestat function for windows.
windows does not have os.path.samestat, and stat().st_ino is always zero,
so util.samestat always returns false on windows.
#!/bin/sh
hg init
echo foo > foo
hg add foo
hg commit -m1 -d"0 0"
echo "# should show copy"
hg copy foo bar
hg debugstate|grep '^copy'
echo "# shouldn't show copy"
hg commit -m2 -d"0 0"
hg debugstate|grep '^copy'
echo "# should match"
hg debugindex .hg/data/foo.i
hg debugrename bar
echo bleah > foo
echo quux > bar
hg commit -m3 -d"0 0"
echo "# should not be renamed"
hg debugrename bar
hg copy -f foo bar
echo "# should show copy"
hg debugstate|grep '^copy'
hg commit -m3 -d"0 0"
echo "# should show no parents for tip"
hg debugindex .hg/data/bar.i
echo "# should match"
hg debugindex .hg/data/foo.i
hg debugrename bar
echo "# should show no copies"
hg debugstate|grep '^copy'
exit 0