for {i++}

 undefined reference to `__emutls_v._ZN6google8protobuf8internal15ThreadSafeArena13thread_cache_E'   增加  IF (WIN32) add_definitions (-DPROTOBUF_USE_DLLS) ENDIF ()

原因是：  listen的socket需要单独设置下，不然有问题 auto fd = evconnlistener_get_fd(listener) set_socket_buffer(fd , MAX_SOCKET_BUFFER )    

set( CMAKE_EXE_LINKER_FLAGS " ${ CMAKE_EXE_LINKER_FLAGS } -Wl,-E ")

 给glog关闭gflags set( WITH_GFLAGS OFF CACHE BOOL "" FORCE )   然后手动添加宏定义即可 add_compile_definitions( HAVE_LIB_GFLAGS )

  cmake -S llvm -B build -G "Unix Makefiles" -DLLVM_ENABLE_PROJECTS="clang" -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind;compiler-rt;libc;openmp" -DCMAKE_BUILD_TYPE=Release   cd build/   make -j8

 原因是没链接pthread库