opensolaris code: translate INVARIANTS to DEBUG and ZFS_DEBUG

Do this by forcing inclusion of
sys/cddl/compat/opensolaris/sys/debug_compat.h
via -include option into all source files from OpenSolaris.
Note that this -include option must always be after -include opt_global.h.

Additionally, remove forced definition of DEBUG for some modules and fix
their build without DEBUG.

Also, meaning of DEBUG was overloaded to enable WITNESS support for some
OpenSolaris (primarily ZFS) locks.  Now this overloading is removed and
that use of DEBUG is replaced with a new option OPENSOLARIS_WITNESS.

MFC after:	17 days

1 files changed, 11 insertions, 0 deletions

diff --git a/UPDATING b/UPDATING
index 0be5b89..d6f0281 100644
--- a/UPDATING
+++ b/UPDATING
@@ -32,6 +32,17 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 10.x IS SLOW:
 	"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
 20130806:
+	INVARIANTS option now enables DEBUG for code with OpenSolaris and
+	Illumos origin, including ZFS.  If you have INVARIANTS in your
+	kernel configuration, then there is no need to set DEBUG or ZFS_DEBUG
+	explicitly.
+	DEBUG used to enable witness(9) tracking of OpenSolaris (mostly ZFS)
+	locks if WITNESS option was set.  Because that generated a lot of
+	witness(9) reports and all of them were believed to be false
+	positives, this is no longer done.  New option OPENSOLARIS_WITNESS
+	can be used to achieve the previous behavior.
+
+20130806:
 	Timer values in IPv6 data structures now use time_uptime instead
 	of time_second.  Although this is not a user-visible functional
 	change, userland utilities which directly use them---ndp(8),