Add comment about why we are using .NOTPARALLEL

diff --git a/Makefile b/Makefile
index ece2886..405537c 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1056,4 +1056,7 @@ stage4:
        echo "XXX TO DO"
        exit 1
 
+
+
+# Don't run the builds in parallel because they are implicitly ordered.
 .NOTPARALLEL: