Can not link libaho-mqtt3cs.so in my project

[WangFengtu1996]

HI,all

• Thanks for your project providing a effective way to link the paho.mqtt.c in my project with cmake.
• But when I use it in my project, I got the error in link step /usr/bin/ld: 找不到 -lpaho-mqtt3cs. I would appreciate it if you could give me some guidance

detail information

• pahomqtt.cmake

include(ExternalProject)
find_package(Git REQUIRED)
find_package(PkgConfig REQUIRED)
pkg_search_module(OPENSSL REQUIRED openssl)

ExternalProject_add(
    pahomqtt
    GIT_REPOSITORY "https://github.com/eclipse/paho.mqtt.c.git"
    GIT_TAG "master"
    UPDATE_COMMAND ""
    PATCH_COMMAND ""
    SOURCE_DIR "${CMAKE_BINARY_DIR}/paho-src"
    CMAKE_ARGS -DPAHO_WITH_SSL=TRUE -DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}/paho-build
)

include_directories(${CMAKE_BINARY_DIR}/paho-build/include)
link_directories(${CMAKE_BINARY_DIR}/paho-build/lib)

• project CMakeLists.txt

include(pahomqtt)
add_dependencies(connect pahomqtt)
target_link_libraries(connect PUBLIC paho-mqtt3cs)  # connect is a dynamic library name compiled

env

• ubuntu 18.04
• cmake version 3.16.0