Both of them.
for i in  linux-2.6-xen  ; do make $i-prep || exit 1; done
make[1]: Entering directory `/usr/src/xen-3.2.0'
make -f buildconfigs/mk.linux-2.6-xen prep
make[2]: Entering directory `/usr/src/xen-3.2.0'
set -e ; \
	if [ ! -e linux-2.6.18-xen.hg/.hg ] ; then \
	    __repo=$(sh buildconfigs/select-repository linux-2.6.18-xen.hg .:..) ; \
	    if [ -d ${__repo} ] ; then \
	        echo "Linking ${__repo} to linux-2.6.18-xen.hg." ; \
	        ln -s ${__repo} linux-2.6.18-xen.hg ; \
	    else \
	        echo "Cloning ${__repo} to linux-2.6.18-xen.hg." ; \
	        hg clone ${__repo#file://} linux-2.6.18-xen.hg ; \
	    fi ; \
	else \
	    __parent=$(hg -R linux-2.6.18-xen.hg path default) ; \
	    echo "Pulling changes from ${__parent} into linux-2.6.18-xen.hg." ; \
	    hg -R linux-2.6.18-xen.hg pull ${__parent} ; \
	fi
select-repository: Searching `.:..' for linux-2.6.18-xen.hg
select-repository: Ignoring `.'
buildconfigs/select-repository: line 35: hg: command not found
select-repository: Unable to determine Xen repository parent.
make[2]: *** [linux-2.6.18-xen.hg/.valid-src] Error 1
make[2]: Leaving directory `/usr/src/xen-3.2.0'
make[1]: *** [linux-2.6-xen-prep] Error 2
make[1]: Leaving directory `/usr/src/xen-3.2.0'