diff --git a/make/qt-defs.mk b/make/qt-defs.mk
index a8fad1a6..c3497d56 100644
--- a/make/qt-defs.mk
+++ b/make/qt-defs.mk
@@ -67,7 +67,7 @@ CPPFLAGS              += -DQT_THREAD_SUPPORT
 	#Qt5Designer  \
 
 ifeq ($(QT_MAJOR_VERSION),5)
-QT_MODULES = \
+QT_MODULES ?= \
 	Qt5Concurrent  \
 	Qt5Core  \
 	Qt5DBus  \
@@ -95,7 +95,7 @@ QT_MODULES = \
 	Qt5XmlPatterns  \
 	Qt5Xml
 else
-QT_MODULES = \
+QT_MODULES ?= \
 	Qt3Support \
 	QtCLucene \
 	QtCore \