diff --git a/src/libs/modelinglib/modelinglib.qbs b/src/libs/modelinglib/modelinglib.qbs
index 2527d139d88..5c8f49f4c46 100644
--- a/src/libs/modelinglib/modelinglib.qbs
+++ b/src/libs/modelinglib/modelinglib.qbs
@@ -3,6 +3,7 @@ import qbs 1.0
 QtcLibrary {
     name: "ModelingLib"
 
+    cpp.defines: base.concat("QMT_LIBRARY")
     cpp.includePaths: base.concat([
         "../3rdparty/modeling",
         "../3rdparty/modeling/qtserialization/inc",