MFC r314651,r318439,r318440:

r314651:

sys/modules: normalize .CURDIR-relative paths to SRCTOP

This simplifies make output/logic

Tested with: `cd sys/modules; make ALL_MODULES=` on amd64

r318439:

Normalize .PATH on SRCTOP

This will help Jenkins dedupe 9 warnings between the static build and
the module build of ipsec(4).

Missed in SRCTOP conversion in r314651.

MFC with: r314651

r318440:

Normalize SYSDIR on SRCTOP instead of .CURDIR

This is being done to simplify pathing for CFLAGS and source files.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Move the old iSCSI initiator source to a more appropriate place
(sys/dev/iscsi_initiator/ instead of sys/dev/iscsi/initiator/), to make
room for the new one. This is also more logical location (kernel module
being named iscsi_initiator.ko, for example). There is no ongoing work
on this I know of, so it shouldn't make life harder for anyone.

There are no functional changes, apart from "svn mv" and adjusting paths.

Fix build.

Unbreak tinderbox.

Fix FreeBSD paradigms in the upstream code.

PR: bin/166933
Submitted by: Garrett Cooper <yanegomi@gmail.com>

Fix LINT builds after r234233; not sure why modules need DEBUG by default.

Update to version 2.3.1.0

Obtained from: Daniel Braniss <danny@cs.huji.ac.il>

Introduce Danny Braniss' iSCSI initiator, version 2.0.99. Please read the
included man pages on how to use it. This code is still somewhat experimental
but has been successfully tested on a number of targets. Many thanks to
Danny for contributing this.

Approved by: re