diff --git a/kstars/configure.in.in b/kstars/configure.in.in
index f5fad3c4..7472b88b 100644
--- a/kstars/configure.in.in
+++ b/kstars/configure.in.in
@@ -46,10 +46,10 @@ if test "${use_libusb}" != false ; then
 	AC_LANG_CPLUSPLUS
 	ac_save_CXXFLAGS="$CXXFLAGS"
 	ac_save_LDFLAGS="$LDFLAGS"
-	if test -z "$qt_includes"; then
+	if test -z "$tqt_includes"; then
 		CXXFLAGS="$CXXFLAGS"
 	else
-		CXXFLAGS="$CXXFLAGS -I$qt_includes"
+		CXXFLAGS="$CXXFLAGS -I$tqt_includes"
 	fi
 	LDFLAGS="$LDFLAGS -ltqt"