undefined reference error when using QT 5.15.2 with cmake

[tedcriss]

Hello, There is a problem when I compile QZXing with QT 5.15.2 + cmake, as pic bellow shows. How can I fix it? This is the CMake file in root dir.

cmake_minimum_required(VERSION 3.5)

project(FileTrans VERSION 0.1 LANGUAGES CXX)

set(CMAKE_INCLUDE_CURRENT_DIR ON)

set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)

set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(QT NAMES Qt6 Qt5 COMPONENTS Widgets Multimedia MultimediaWidgets REQUIRED)
find_package(Qt${QT_VERSION_MAJOR} COMPONENTS Widgets Multimedia MultimediaWidgets REQUIRED)

include_directories(${Qt5MultimediaWidgets_INCLUDE_DIRS})
include_directories(QZXing)

set(PROJECT_SOURCES
        main.cpp
        widget.cpp
        widget.h
        widget.ui
        QrCode.cpp
        QrSegment.cpp
        BitBuffer.cpp
        BitBuffer.h
        QrCode.h
        QrSegment.h
        QtCameraCapture.h
        QtCameraCapture.cpp
)

add_subdirectory(QZXing)

if(${QT_VERSION_MAJOR} GREATER_EQUAL 6)
    qt_add_executable(FileTrans
        MANUAL_FINALIZATION
        ${PROJECT_SOURCES}
    )
# Define target properties for Android with Qt 6 as:
#    set_property(TARGET FileTrans APPEND PROPERTY QT_ANDROID_PACKAGE_SOURCE_DIR
#                 ${CMAKE_CURRENT_SOURCE_DIR}/android)
# For more information, see https://doc.qt.io/qt-6/qt-add-executable.html#target-creation
else()
    if(ANDROID)
        add_library(FileTrans SHARED
            ${PROJECT_SOURCES}
        )
# Define properties for Android with Qt 5 after find_package() calls as:
#    set(ANDROID_PACKAGE_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/android")
    else()
        add_executable(FileTrans
            ${PROJECT_SOURCES}
        )
    endif()
endif()

target_link_libraries(FileTrans PRIVATE Qt${QT_VERSION_MAJOR}::Widgets Qt${QT_VERSION_MAJOR}::Multimedia Qt${QT_VERSION_MAJOR}::MultimediaWidgets QZXing)

set_target_properties(FileTrans PROPERTIES
    MACOSX_BUNDLE_GUI_IDENTIFIER my.example.com
    MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
    MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
)

if(QT_VERSION_MAJOR EQUAL 6)
    qt_finalize_executable(FileTrans)
endif()

files