1.8 release
    libndp,ndptool: use poll() instead of select()
    libndp: avoid static buffer for debug string in ndp_sock_recv()
    ndptool: avoid static buffer for string in ndptool
    libndp: use thread local variables for static return arguments
    ndptool: don't use static variable for local context in msgrcv_handler_func()
    ndptool: fix printing dnssl lifetime in ndptool
    ndptool: fix potential memory leak caused by strdup
    ndptool: add -D dest support
    libndp: fix nd_msg typo when setting target address
    libndp: close sockfd after using to avoid handle leak
    ndptool: fix target parameter typo
    ndptool: add -T target support