cmake HAVE_DAG_STREAMS_API examples

CTSRD-CHERI/cheribsd contrib/libpcap/CMakeLists.txt :2561 

check_function_exists(dag_attach_stream HAVE_DAG_STREAMS_API)

asset-group/5ghoul-5g-nr-attacks libs/libpcap/CMakeLists.txt :1744 

check_function_exists(dag_attach_stream HAVE_DAG_STREAMS_API)