Extract eventfilter declarations to sys/_eventfilter.h

This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.

EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).

As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions.  The remainder of the patch addresses
adding appropriate includes to fix those files.

LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).

No functional change (intended).  Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed.  __FreeBSD_version has been bumped.

3 files changed, 4 insertions, 0 deletions

diff --git a/sys/dev/dcons/dcons_crom.c b/sys/dev/dcons/dcons_crom.c
index 6bba3857d1b9..2a320ef65f3d 100644
--- a/sys/dev/dcons/dcons_crom.c
+++ b/sys/dev/dcons/dcons_crom.c
@@ -38,6 +38,7 @@
  */
 
 #include <sys/param.h>
+#include <sys/eventhandler.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
 #include <sys/systm.h>
diff --git a/sys/dev/dcons/dcons_os.c b/sys/dev/dcons/dcons_os.c
index 6853515c6820..97a00760d031 100644
--- a/sys/dev/dcons/dcons_os.c
+++ b/sys/dev/dcons/dcons_os.c
@@ -37,6 +37,7 @@
  */
 
 #include <sys/param.h>
+#include <sys/eventhandler.h>
 #include <sys/kdb.h>
 #include <gdb/gdb.h>
 #include <sys/kernel.h>
diff --git a/sys/dev/dcons/dcons_os.h b/sys/dev/dcons/dcons_os.h
index 7421b4734d78..b8fc3afc39ef 100644
--- a/sys/dev/dcons/dcons_os.h
+++ b/sys/dev/dcons/dcons_os.h
@@ -36,6 +36,8 @@
  * $FreeBSD$
  */
 
+#include <sys/_eventhandler.h>
+
 typedef void (*dcons_poll_fn)(void *, int);
 EVENTHANDLER_DECLARE(dcons_poll, dcons_poll_fn);