- Fix POSIX setting of non-blocking mode (we were clearing the R/W flags)

- Close-on-exec: Don't leak httpd client sockets into CGI scripts or
  whatever child process we spawn.

src/network/httpd.c

@@ -2448,7 +2448,13 @@ static void httpd_HostThread( httpd_host_t *host )
                         ioctlsocket( fd, FIONBIO, &i_dummy );
                     }
 #else
-                    fcntl( fd, F_SETFL, O_NONBLOCK );
+                    fcntl( fd, F_SETFD, FD_CLOEXEC );
+                    {
+                        int i_val = fcntl( fd, F_GETFL );
+                        fcntl( fd, F_SETFL,
+                               O_NONBLOCK | (i_val != -1) ? i_val : 0 );
+                    }
+
                     if( fd >= FD_SETSIZE )
                     {
                         net_Close( fd );