Cmake cross compilation

        The original CMakeLists.txt The contents of the remain unchanged . Add a new file , Such as toolChain.cmake

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_C_COMPILER /opt/tools/cgtools/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/bin/aarch64-none-linux-gnu-gcc)
set(CMAKE_CXX_COMPILER /opt/tools/cgtools/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/bin/aarch64-none-linux-gnu-g++)
set(CMAKE_CROSSCOMPILING TRUE)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(CMAKE_FIND_ROOT_PATH /opt/tools/cgtools/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/aarch64-none-linux-gnu/lib64 
                        /opt/cross/3rdparty/include 
                        /opt/cross/3rdparty/lib/aarch64)

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER) # Executable programs are not just set ROOT_PATH lookup 
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)  # Only in settings ROOT_PATH Find library under 
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)  # Only in settings ROOT_PATH Find the header file 

        Running cmake When it's time to specify TOOLCHAIN_FILE, Such as ：cmake -DCMAKE_TOOLCHAIN_FILE=./toolChain.cmake ..

        then make that will do