cmake HAVE_TCP_KEEPINTVL examples

htcondor/htcondor build/cmake/CondorConfigure.cmake :344 

check_symbol_exists(TCP_KEEPINTVL, "sys/types.h;sys/socket.h;netinet/tcp.h" HAVE_TCP_KEEPINTVL)

syslog-ng/syslog-ng CMakeLists.txt :145 

check_symbol_exists(TCP_KEEPINTVL "sys/socket.h;netinet/in.h;netinet/tcp.h" HAVE_TCP_KEEPINTVL)