+/* 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. */
+
+/* #define HAVE_LINUX_SENDFILE */
+
+#define F_FREESP O_TRUNC
+typedef struct flock flock_t;
+
+#define os_strsignal strsignal
+#define OS_STRSIGNAL
+
+#if defined(__linux__) || defined(__FreeBSD_kernel__) || defined(__NetBSD_kernel__)
+#define SIOCGIFCONF_GIVES_ADDR
+#define HAVE_SYS_MOUNT_H
+#endif
+
+#if defined(__linux__)
+