diff --git a/qtcreator.pri b/qtcreator.pri
index 507e19f7114cd16964dbc6e1d3c668fcfbb16bb6..8b2268ca3ffc886d498b80b323efde0ced17a28c 100644
--- a/qtcreator.pri
+++ b/qtcreator.pri
@@ -1,3 +1,6 @@
+!isEmpty(QTCREATOR_PRI_INCLUDED):error("qtcreator.pri already included")
+QTCREATOR_PRI_INCLUDED = 1
+
 defineReplace(cleanPath) {
     win32:1 ~= s|\\\\|/|g
     contains(1, ^/.*):pfx = /