qt 添加dll

SOURCES += \
    main.cpp \
    mainwindow.cpp \
    xxxx.cpp

HEADERS += \
    mainwindow.h \
    xxx/xx/xxx.h \
    xxxx.h

FORMS += \
    mainwindow.ui

DISTFILES += \
    xxx/xx/xxxx.lib \
    xxxx/xxx/xxxx.dll \

LIBS += -L$$PWD/xxx/xxx/ -lxxxx