Compile failed in Linux.

[sbilly]

cd zerotier-build/libzt
cmake .
make 

it cause

[ 50%] Building CXX object CMakeFiles/ipv6adhocclient.dir/examples/bindings/cpp/ipv6adhoc/ipv6adhocclient.cpp.o
/tmp/zerotier-build/libzt/examples/bindings/cpp/ipv6adhoc/ipv6adhocclient.cpp: In function ‘int main(int, char**)’:
/tmp/zerotier-build/libzt/examples/bindings/cpp/ipv6adhoc/ipv6adhocclient.cpp:89:28: warning: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 2 has type ‘uint64_t {aka long unsigned int}’ [-Wformat=]
  printf("nwid=%llx\n", nwid);
                            ^
[ 51%] Linking CXX executable bin/ipv6adhocclient
bin/lib/libzt.a(ZT1Service.cpp.o): In function `zts_start':
ZT1Service.cpp:(.text+0x1631): undefined reference to `pthread_create'
bin/lib/libzto.a(EmbeddedNetworkController.cpp.o): In function `std::thread::thread<ZeroTier::EmbeddedNetworkController::_startThreads()::{lambda()#1}>(ZeroTier::EmbeddedNetworkController::_startThreads()::{lambda()#1}&&)':
EmbeddedNetworkController.cpp:(.text+0xf81a): undefined reference to `pthread_create'
bin/lib/libzt.a(VirtualTap.cpp.o): In function `ZeroTier::Thread::join(ZeroTier::Thread const&)':
VirtualTap.cpp:(.text._ZN8ZeroTier6Thread4joinERKS0_[_ZN8ZeroTier6Thread4joinERKS0_]+0x28): undefined reference to `pthread_join'
bin/lib/libzt.a(VirtualTap.cpp.o): In function `ZeroTier::Thread ZeroTier::Thread::start<VirtualTap>(VirtualTap*)':
VirtualTap.cpp:(.text._ZN8ZeroTier6Thread5startI10VirtualTapEES0_PT_[_ZN8ZeroTier6Thread5startI10VirtualTapEES0_PT_]+0x47): undefined reference to `pthread_attr_setstacksize'
VirtualTap.cpp:(.text._ZN8ZeroTier6Thread5startI10VirtualTapEES0_PT_[_ZN8ZeroTier6Thread5startI10VirtualTapEES0_PT_]+0x63): undefined reference to `pthread_create'
bin/lib/liblwip.a(sys_arch.c.o): In function `sys_thread_new':
sys_arch.c:(.text+0xb8): undefined reference to `pthread_create'
bin/lib/liblwip.a(sys_arch.c.o): In function `sys_sem_new_internal':
sys_arch.c:(.text+0x716): undefined reference to `pthread_condattr_setclock'
collect2: error: ld returned 1 exit status
CMakeFiles/ipv6adhocclient.dir/build.make:101: recipe for target 'bin/ipv6adhocclient' failed
make[2]: *** [bin/ipv6adhocclient] Error 1
CMakeFiles/Makefile2:147: recipe for target 'CMakeFiles/ipv6adhocclient.dir/all' failed
make[1]: *** [CMakeFiles/ipv6adhocclient.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2