Backport r68338: Make sure to checkout any new packages
diff --git a/Misc/build.sh b/Misc/build.sh
index 423e96d..43b3ce4 100755
--- a/Misc/build.sh
+++ b/Misc/build.sh
@@ -263,7 +263,7 @@
     echo "Conflict detected in $CONFLICTED_FILE.  Doc build skipped." > ../build/$F
     err=1
 else
-    make update html >& ../build/$F
+    make checkout update html >& ../build/$F
     err=$?
 fi
 update_status "Making doc" "$F" $start