fix tests on FreeBSD 238b761 introduced a test for posix behaviour, but on FreeBSD some of the structs and constants used aren't defined in <arpa/inet.h>. Include the appropriate headers to get the tests working again on FreeBSD.
diff --git a/tests-clar/core/posix.c b/tests-clar/core/posix.c
index 0d9443f..890e25d 100644
--- a/tests-clar/core/posix.c
+++ b/tests-clar/core/posix.c
@@ -1,5 +1,7 @@
#ifndef _WIN32
# include <arpa/inet.h>
+# include <sys/socket.h>
+# include <netinet/in.h>
#else
# include <ws2tcpip.h>
# ifdef _MSC_VER