diff --git a/scripts/build.sh b/scripts/build.sh
index aa53269b1..c1be9a1cb 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -221,7 +221,8 @@ echo Building from "$SRC", installing in "$INSTALL_ROOT"
 # find qmake
 if [ -n "$CMAKE_PREFIX_PATH" ] ; then
 	QMAKE=$CMAKE_PREFIX_PATH/../../bin/qmake
-else
+fi
+if [[ -z $QMAKE  ||  ! -x $QMAKE ]] ; then
 	hash qmake > /dev/null 2> /dev/null && QMAKE=qmake
 	[ -z $QMAKE ] && hash qmake-qt5 > /dev/null 2> /dev/null && QMAKE=qmake-qt5
 	[ -z $QMAKE ] && echo "cannot find qmake or qmake-qt5" && exit 1