--- a/src/qtgui/recoll.pro
+++ b/src/qtgui/recoll.pro
@@ -3,7 +3,8 @@
 
 CONFIG	+= qt warn_on release
 
-SOURCES	+= main.cpp
+SOURCES	+= main.cpp \
+	idxthread.cpp
 
 FORMS	= recollmain.ui