cmake HAVE_LIBNL examples

CTSRD-CHERI/cheribsd contrib/libpcap/CMakeLists.txt :2058 

check_function_exists(nl_socket_alloc HAVE_LIBNL)

CTSRD-CHERI/cheribsd contrib/libpcap/CMakeLists.txt :2072 

unset(HAVE_LIBNL CACHE)

asset-group/5ghoul-5g-nr-attacks libs/libpcap/CMakeLists.txt :1321 

check_function_exists(nl_socket_alloc HAVE_LIBNL)

asset-group/5ghoul-5g-nr-attacks libs/libpcap/CMakeLists.txt :1332 

unset(HAVE_LIBNL CACHE)