Error when enabled QRCODE.

lude/QtCore -Ibuild -Ibuild -I../mxe/usr/i686-w64-mingw32.static/qt5/mkspecs/win32-g++  -o build/qrcodedialog.o src/qt/qrcodedialog.cpp
src/qt/qrcodedialog.cpp:12:22: fatal error: qrencode.h: No such file or directory
compilation terminated.
Makefile.Release:94227: recipe for target 'build/qrcodedialog.o' failed
make: *** [build/qrcodedialog.o] Error 1


How to fix it ?