dispatch: parse and apply -R early
This allows us to use extensions specified in .hg/hgrc. Unfortunately,
this requires us to parse that file twice, but performance impact on
the version command appears to be less than 1%.
#!/bin/sh
echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH
hg init a
cd a
echo 'base' > base
hg ci -Ambase -d '1 0'
hg qnew -mmqbase mqbase
hg qsave
hg qrestore 2