cmake HAVE_SO_NONBLOCK examples

fluent/fluent-bit lib/c-ares-1.34.4/CMakeLists.txt :399 

CHECK_SYMBOL_EXISTS (SO_NONBLOCK     "${CMAKE_EXTRA_INCLUDE_FILES}" HAVE_SO_NONBLOCK)

Studio3T/robomongo src/third-party/libssh2-1.7.0/sources/cmake/CheckNonblockingSocketSupport.cmake :100 

check_c_source_compiles("/* SO_NONBLOCK test (BeOS) */
#include <socket.h>

int main()
{
    long b = 1;
    int socket;
    int flags = setsockopt(socket, SOL_SOCKET, SO_NONBLOCK, &b, sizeof(b));
}"
          HAVE_SO_NONBLOCK)

Studio3T/robomongo src/third-party/libssh2-1.9.0/sources/cmake/CheckNonblockingSocketSupport.cmake :100 

check_c_source_compiles("/* SO_NONBLOCK test (BeOS) */
#include <socket.h>

int main()
{
    long b = 1;
    int socket;
    int flags = setsockopt(socket, SOL_SOCKET, SO_NONBLOCK, &b, sizeof(b));
}"
          HAVE_SO_NONBLOCK)