cmake not working with static compiled qt

[Mr Pang]

I have a custom static compiled qt version installing to /opt/qt593.
And I found cmake generate wrong linking flags.
Here is my CMakeLists.txt

cmake_minimum_required(VERSION 3.0.0)

project(untitled2 VERSION 0.1 LANGUAGES CXX)

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)

set(Qt5Core_DIR "/opt/qt593/lib/cmake/Qt5Core")

find_package(Qt5Core)

add_executable(${PROJECT_NAME} "main.cpp")

target_link_libraries(${PROJECT_NAME} Qt5::Core)

And the final linking command is

/usr/bin/c++      CMakeFiles/untitled2.dir/main.cpp.o CMakeFiles/untitled2.dir/untitled2_automoc.cpp.o  -o untitled2 -rdynamic /opt/qt593/lib/libQt5Core.a

There are a lot of undefined symbols. It seems that cmake forgets low level system libraries such as glib pthread,etc.

Any ideas?

If I switch to qmake, then all is OK.

[Mr Pang]

grep pthread /opt/qt593/lib/pkgconfig/ -rn 
grep pthread /opt/qt593/lib/cmake/ -rn

And I found that there are lots of matches in pkgconfig, but nothing matches in cmake. So maybe this is a installation bug.