Update build system and packaging

Minimal changes required to integrate the SPL sources in to the
ZFS repository build infrastructure and packaging.

Build system and packaging:
  * Renamed SPL_* autoconf m4 macros to ZFS_*.
  * Removed redundant SPL_* autoconf m4 macros.
  * Updated the RPM spec files to remove SPL package dependency.
  * The zfs package obsoletes the spl package, and the zfs-kmod
    package obsoletes the spl-kmod package.
  * The zfs-kmod-devel* packages were updated to add compatibility
    symlinks under /usr/src/spl-x.y.z until all dependent packages
    can be updated.  They will be removed in a future release.
  * Updated copy-builtin script for in-kernel builds.
  * Updated DKMS package to include the spl.ko.
  * Updated stale AUTHORS file to include all contributors.
  * Updated stale COPYRIGHT and included the SPL as an exception.
  * Renamed README.markdown to README.md
  * Renamed OPENSOLARIS.LICENSE to LICENSE.
  * Renamed DISCLAIMER to NOTICE.

Required code changes:
  * Removed redundant HAVE_SPL macro.
  * Removed _BOOT from nvpairs since it doesn't apply for Linux.
  * Initial header cleanup (removal of empty headers, refactoring).
  * Remove SPL repository clone/build from zimport.sh.
  * Use of DEFINE_RATELIMIT_STATE and DEFINE_SPINLOCK removed due
    to build issues when forcing C99 compilation.
  * Replaced legacy ACCESS_ONCE with READ_ONCE.
  * Include needed headers for `current` and `EXPORT_SYMBOL`.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
TEST_ZIMPORT_SKIP="yes"
Closes #7556

include/sys/zfs_context.h

@@ -32,31 +32,25 @@
 
 #include <sys/note.h>
 #include <sys/types.h>
-#include <sys/t_lock.h>
 #include <sys/atomic.h>
 #include <sys/sysmacros.h>
-#include <sys/bitmap.h>
+#include <sys/vmsystm.h>
+#include <sys/condvar.h>
 #include <sys/cmn_err.h>
 #include <sys/kmem.h>
 #include <sys/kmem_cache.h>
 #include <sys/vmem.h>
 #include <sys/taskq.h>
-#include <sys/buf.h>
 #include <sys/param.h>
-#include <sys/systm.h>
-#include <sys/cpuvar.h>
 #include <sys/kobj.h>
-#include <sys/conf.h>
 #include <sys/disp.h>
 #include <sys/debug.h>
 #include <sys/random.h>
+#include <sys/strings.h>
 #include <sys/byteorder.h>
-#include <sys/systm.h>
 #include <sys/list.h>
 #include <sys/uio_impl.h>
-#include <sys/dirent.h>
 #include <sys/time.h>
-#include <vm/seg_kmem.h>
 #include <sys/zone.h>
 #include <sys/sdt.h>
 #include <sys/kstat.h>
@@ -76,8 +70,6 @@
 #define	_SYS_MUTEX_H
 #define	_SYS_RWLOCK_H
 #define	_SYS_CONDVAR_H
-#define	_SYS_SYSTM_H
-#define	_SYS_T_LOCK_H
 #define	_SYS_VNODE_H
 #define	_SYS_VFS_H
 #define	_SYS_SUNDDI_H