Bring over illumos ZFS FMA logic -- phase 1

This first phase brings over the ZFS SLM module, zfs_mod.c, to handle
auto operations in response to disk events. Disk event monitoring is
provided from libudev and generates the expected payload schema for
zfs_mod. This work leverages the recently added devid and phys_path
strings in the vdev label.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Don Brady <don.brady@intel.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #4673

cmd/zed/zed_disk_event.h

@@ -0,0 +1,31 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License Version 1.0 (CDDL-1.0).
+ * You can obtain a copy of the license from the top-level file
+ * "OPENSOLARIS.LICENSE" or at <http://opensource.org/licenses/CDDL-1.0>.
+ * You may not use this file except in compliance with the license.
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2016, Intel Corporation.
+ */
+
+#ifndef	ZED_DISK_EVENT_H
+#define	ZED_DISK_EVENT_H
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+extern int zed_disk_event_init(void);
+extern void zed_disk_event_fini(void);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* !ZED_DISK_EVENT_H */