Only read .hg/hgrc files from trusted users/groups
The list of trusted users and groups is specified in the [trusted]
section of a hgrc; the current user is always trusted; "*" can be
used to trust all users/groups.
Global hgrc files are always read.
On Windows (and other systems that don't have the pwd and grp modules),
all .hg/hgrc files are read.
This is essentially the same patch that was previously applied as
revision 494521a3f142.
#!/bin/sh
echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH
cat > $HGTMP/false <<EOF
#!/bin/sh
exit 1
EOF
chmod +x $HGTMP/false
hg init foo
cd foo
echo foo > foo
hg add foo
# mq may keep a reference to the repository so __del__ will not be called
# and .hg/journal.dirstate will not be deleted:
HGEDITOR=$HGTMP/false hg ci
HGEDITOR=$HGTMP/false hg ci
exit 0