package/zxing-cpp: add opencv3 optional dependency

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr: split to a separate condition]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit a25793ba0403f5073f606f8323c74209d21bc894)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/zxing-cpp/zxing-cpp.mk

@@ -19,6 +19,9 @@ endif
 ifeq ($(BR2_PACKAGE_OPENCV_LIB_HIGHGUI),y)
 ZXING_CPP_DEPENDENCIES += opencv
 ZXING_CPP_CONF_OPTS += -DBUILD_OPENCV=ON
+else ifeq ($(BR2_PACKAGE_OPENCV3_LIB_HIGHGUI),y)
+ZXING_CPP_DEPENDENCIES += opencv3
+ZXING_CPP_CONF_OPTS += -DBUILD_OPENCV=ON
 else
 ZXING_CPP_CONF_OPTS += -DBUILD_OPENCV=OFF
 endif