Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Correct double "the the"

Approved by: cperciva
MFC after: 3 days

- remove non-existent input directories from the configs
- add the target-arch to the project name where applicable (arch dependend code)
- fix comment for __FreeBSD__ [1]

Noticed by: bz [1]

Just define __FreeBSD__ to 1 instead of doing what the compiler does.
The kernel is supposed to DTRT based upon the __FreeBSD_version value,
not the value of __FreeBSD__.

Discussed with: bz

We are in FreeBSD 10 now: define __FreeBSD__ to 10.

Mechanically add a config for all missing drivers.

No cross-referencing was added to the configs, so no
automatic linking to the documentation of other subsystems.

Drivers which already contain doxygen markup:
agp ath bktr bxe cxgb cxgbe dpt drm e1000 iir
ixgbe mwl nxge ofw pccard siba wpi xen

- Update config to doxygen 1.5.2 (I use this with 1.5.9).
- Add linprocfs and linsysfs to the linuxulator dox.
- Take the generated includes from the .m files from a subdirectory
instead of putting everything into $(.OBJDIR). This imporves the
human readbility of the source directory contents a lot, if you do not
create a separate OBJDIR.
- Assume UTF-8 encoding for every input file.
- Strip the source and dest path from the output, we are not interested
in the absolute location on the machine where the docs are created,
relative the the root of the FreeBSD source is what interests us.
- Exclude .svn directories.
- Switch to alphabetic index.
- Use one line per INCLUDE_PATH member in the common dox-config.
- Bump the __FreeBSD__ version to 9. [MFC: to 8]
- Switch from hardcoded .m files to an run-time generated one. Takes
a little bit more time to get started with actual work, but at least
is more future-proof. If you generate dox for all subsystems, the
time to find all .m files in the source is magnitutes lower than
producing the docs.
- Make the *DEST_PATH overidable from the environment. This allows to
produce the output directly in the docroot of a webserver.
- Fix the path when telling the user where he can find the API docs.

MFC after: 1 month (after 8.0)

Remove ISDN4BSD (I4B) from HEAD as it is not MPSAFE and
parts relied on the now removed NET_NEEDS_GIANT.
Most of I4B has been disconnected from the build
since July 2007 in HEAD/RELENG_7.

This is what was removed:
- configuration in /etc/isdn
- examples
- man pages
- kernel configuration
- sys/i4b (drivers, layers, include files)
- user space tools
- i4b support from ppp
- further documentation

Discussed with: rwatson, re

- Chase for crypto_if.m -> crytpodev_if.m rename in order to
fix doxygen generation.
- Add some missing *_if.m files.

Approved by: re (hrs)

ah_if.m was removed a while ago

Fix build when .CURDIR != .OBJDIR.

Noticed by: "Alexander Mogilny" <sg@astral.ntu-kpi.kiev.ua>

Add (missing) and remove (obsolete) .m files.

Add a disclaimer regarding public/internal functions to every subsystem for
now.

Discussed on: cvs-all
Helped with the wording: "Ben Kaduk" <minimarmot@gmail.com>

This is the kernel subsystem API documentation generation framework.

It uses doxygen to generate the API documentation. For each subsystem
a very small (about 20 lines with comments) subsystem specific Doxyfile
has to be written (have a look at the README for more). All common doxygen
options are specified in a separate file.

The framework is configured to not only generate the HTML version, but also
a PDF version (the paper size is hardcoded to DIN A4 currently and depending
on the subsystem you have to increase some limits in the latex configuration
of your system, the README tells more about this).

It also allows cross-references between the subsystems (it generates doxygen
tag files).

Currently the docs are generated in OBJDIR, but this may change after
coordination with doc@. The makefile is prepared to generate/move various
parts of the generated docs to different destinations.

TARGET_ARCH is respected and some env-vars are set for architecture specific
handling of the source (the README tells more).

Subsystems for which docs are generated:
- cam - crypto - dev_pci
- dev_sound - dev_usb - geom
- i4b - kern - libkern
- linux - net80211 - netgraph
- netinet - netinet6 - netipsec
- opencrypto - vm

Requested by: gnn

Experimental support for using doxygen to generate kernel documentation.