diff --git a/configure b/configure
index 2a7d62e2..b8ac30f2 100755
--- a/configure
+++ b/configure
@@ -489,7 +489,7 @@ def create_ninja_and_rc(l_installed):
         'function qp_prepend_export () {',
         '  #Prepend path $2:${!1}. Add the semicolon only if ${!1} is defined',
         '  eval "value_1=\"\${$1}\""',
-        '  echo ${value_1:+${value_1}:}${2}',
+        '  echo ${value_1:+${2}:${value_1}}',
         '}',
         'export PYTHONPATH=$(qp_prepend_export "PYTHONPATH" "${QP_EZFIO}/Python":"${QP_PYTHON}")',
         'export PATH=$(qp_prepend_export "PATH" "${QP_PYTHON}":"${QP_ROOT}"/bin:"${QP_ROOT}"/ocaml)',