diff --git a/tools/build-system/hudson-sflphone-script.sh b/tools/build-system/hudson-sflphone-script.sh
index 47b9795dbcb2465e44635780729af96738905ae7..6cc272a577386bcb28f48e1444d1eefb5525cffe 100755
--- a/tools/build-system/hudson-sflphone-script.sh
+++ b/tools/build-system/hudson-sflphone-script.sh
@@ -115,7 +115,7 @@ function launch_functional_test_daemon {
 
 function build_contrib {
     pushd contrib
-    mkdir -f native
+    mkdir -p native
     pushd native
     ../bootstrap
     make