/* When using the DKIM, setting HAVE_LINUX_SENDFILE can increase
performance on outgoing mail a bit. Note: With older glibc versions
this setting will conflict with the _FILE_OFFSET_BITS=64 setting
-defined as part of the Linux CFLAGS. */
+defined as part of the Linux CFLAGS. As of 2017 those are declared
+to be too old to build by default. */
-/* #define HAVE_LINUX_SENDFILE */
+#define HAVE_LINUX_SENDFILE
#define F_FREESP O_TRUNC
typedef struct flock flock_t;
# define EXIM_HAVE_OPENAT
#endif
+#include <netinet/tcp.h> /* for TCP_FASTOPEN */
+#include <sys/socket.h> /* for MSG_FASTOPEN */
#if defined(TCP_FASTOPEN) && !defined(MSG_FASTOPEN)
# define MSG_FASTOPEN 0x20000000
#endif