-- Build files have been written to: /home/pi/Downloads/ot-br-posix/build/otbr
[1/1] Linking CXX executable src/web/otbr-web
FAILED: src/web/otbr-web 
: && /usr/bin/c++     src/web/CMakeFiles/otbr-web.dir/main.cpp.o src/web/CMakeFiles/otbr-web.dir/web-service/ot_client.cpp.o src/web/CMakeFiles/otbr-web.dir/web-service/web_server.cpp.o src/web/CMakeFiles/otbr-web.dir/web-service/wpan_service.cpp.o  -o src/web/otbr-web -L/usr/local/lib -Wl,-rpath,/usr/local/lib: -ljsoncpp src/common/libotbr-common.a src/utils/libotbr-utils.a third_party/openthread/repo/src/core/libopenthread-ftd.a third_party/openthread/repo/src/posix/platform/libopenthread-posix.a third_party/openthread/repo/third_party/mbedtls/repo/library/libmbedtls.a /usr/lib/arm-linux-gnueabihf/libboost_filesystem.so /usr/lib/arm-linux-gnueabihf/libboost_system.so -lpthread src/common/libotbr-common.a third_party/openthread/repo/third_party/mbedtls/repo/library/libmbedx509.a third_party/openthread/repo/third_party/mbedtls/repo/library/libmbedcrypto.a third_party/openthread/repo/src/lib/platform/libopenthread-platform.a -lutil && :
/usr/bin/ld: src/web/CMakeFiles/otbr-web.dir/web-service/web_server.cpp.o: undefined reference to symbol 'epoll_create@@GLIBC_2.4'
/usr/bin/ld: //lib/arm-linux-gnueabihf/libc.so.6: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.