Add FreeBSD connection timeout socket option

On FreeBSD, the option to configure connection timeout is called
TCP_KEEPINIT, use it to configure the connection timeout there.

This also fixes the dangling socket problems in the unit test, so
re-enable them.

lib/isc/netmgr/netmgr.c

@@ -2283,6 +2283,10 @@ isc__nm_socket_dontfrag(uv_os_sock_t fd, sa_family_t sa_family) {
 #define TIMEOUT_TYPE	unsigned int
 #define TIMEOUT_DIV	1
 #define TIMEOUT_OPTNAME TCP_USER_TIMEOUT
+#elif defined(TCP_KEEPINIT)
+#define TIMEOUT_TYPE	int
+#define TIMEOUT_DIV	1000
+#define TIMEOUT_OPTNAME TCP_KEEPINIT
 #endif
 
 isc_result_t

lib/isc/tests/tcp_quota_test.c

@@ -9,7 +9,7 @@
  * information regarding copyright ownership.
  */
 
-#if HAVE_CMOCKA && defined(__linux__)
+#if HAVE_CMOCKA
 #include <sched.h> /* IWYU pragma: keep */
 #include <setjmp.h>
 #include <stdarg.h>

lib/isc/tests/tcp_test.c

@@ -9,7 +9,7 @@
  * information regarding copyright ownership.
  */
 
-#if HAVE_CMOCKA && defined(__linux__)
+#if HAVE_CMOCKA
 #include <sched.h> /* IWYU pragma: keep */
 #include <setjmp.h>
 #include <stdarg.h>

lib/isc/tests/tcpdns_test.c

@@ -9,7 +9,7 @@
  * information regarding copyright ownership.
  */
 
-#if HAVE_CMOCKA && defined(__linux__)
+#if HAVE_CMOCKA
 #include <sched.h> /* IWYU pragma: keep */
 #include <setjmp.h>
 #include <stdarg.h>

lib/isc/tests/udp_test.c

@@ -9,7 +9,7 @@
  * information regarding copyright ownership.
  */
 
-#if HAVE_CMOCKA && defined(__linux__)
+#if HAVE_CMOCKA
 #include <sched.h> /* IWYU pragma: keep */
 #include <setjmp.h>
 #include <stdarg.h>