The same duplicate build avoidance as in Doit.

Signed-off-by: Junio C Hamano <junkio@cox.net>

DoKernelOrg

@@ -14,9 +14,30 @@ make clean >/dev/null 2>&1 &&
 case "$1" in
 '')
 	echo "* Building all"
+	branches='naster master maint'
+
+	# Make sure naster is between master and pu if exists
+	if naster=`git rev-parse --verify refs/heads/naster 2>/dev/null`
+	then
+		master=`git rev-parse --verify refs/heads/master` &&
+		pu=`git rev-parse --verify refs/heads/pu` &&
+		MBM=`git merge-base --all $naster $master` &&
+		MBN=`git merge-base --all $naster $pu` &&
+		case ",$MBM,$MBN," in
+		",$master,$naster,") ;;
+		*)	echo >&2 "naster is not between master and pu"
+			exit 1 ;;
+		esac
+		# If naster is the same as pu, no point rebuilding pu.
+		case ",$naster,$pu," in
+		",$pu,$naster,") ;;
+		*) branches="$branches pu" ;;
+		esac
+	fi
+
 	{
 		nstalled=install
-		for branch in naster master maint pu
+		for branch in $branches
 		do
 			if git-rev-parse --verify refs/heads/$branch 2>/dev/null
 			then