make appendfile simpler so it does not break with revlogng on windows. it used to cache open files. this made revlogng break because it wants to rename files when splitting .i into .i/.d, but cannot rename or unlink open files on windows. new code is bit slower, but safe on linux and windows. proper fix for too many open/close of changelog/manifest belongs in different place. can get 10% speed improvement back.

#!/bin/sh -e

umask 027
mkdir test1
cd test1

hg init
touch a b
hg add a b
hg ci -m "added a b" -d "1000000 0"

cd ..
mkdir test2
cd test2

hg init
hg pull ../test1
hg co
chmod +x a
hg ci -m "chmod +x a" -d "1000000 0"

cd ../test1
echo 123 >>a
hg ci -m "a updated" -d "1000000 0"

hg pull ../test2
hg heads
hg history

hg -v co -m

ls -l ../test[12]/a > foo
cut -b 1-10 < foo