include: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c comment pattern

Remove /^/[*/]\s*\$FreeBSD\$.*\n/

include: General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Remove the const qualifier from iconv(3) to comply with POSIX:
http://pubs.opengroup.org/onlinepubs/9699919799/functions/iconv.html

Adjust all code that calls iconv.

PR: 199099
Exp-run by: antoine
MFC after: 2 weeks

Add ICONV_{GET,SET}_ILSEQ_INVALID iconvctl. GNU iconv returns EILSEQ
when there is an invalid character in the output codeset while it is
valid in the input. However, POSIX requires iconv() to perform an
implementation-defined conversion on the character. So, Citrus iconv converts
such a character to a special character which means it is invalid in the
output codeset.

This is not a problem in most cases but some software like libxml2 depends
on GNU's behavior to determine if a character is output as-is or another form
such as a character entity (&#NNN;).

Attempt to move the POSIX iconv* symbols out of runtime linker space.
FreeBSD systems usually implemented this as a third party module and
our implementation hasn't played as nicely with the old way as it could
have.

To that end:
* Rename the iconv* symbols in libc.so.7 to have a __bsd_ prefix.
* Provide .symver compatability with existing 10.x+ binaries that
referenced the iconv symbols. All existing binaries should work.
* Like on Linux/glibc systems, add a libc_nonshared.a to the ldscript
at /usr/lib/libc.so.
* Move the "iconv*" wrapper symbols to libc_nonshared.a

This should solve the runtime ambiguity about which symbols resolve
to where. If you compile against the iconv in libc, your runtime
dependencies will be unambiguous.

Old 9.x libraries and binaries will always resolve against their
libiconv.so.3 like they did on 9.x. They won't resolve against libc.

Old 10.x binaries will be satisified by the .symver helpers.

This should allow ports to selectively compile against the libiconv
port if needed and it should behave without ambiguity now.

Discussed with: kib

Remove the WITH_LIBICONV_COMPAT hack that seems to do more harm than
good. This caused libc to spoof the ports libiconv namespace and
provide a colliding libiconv.so.3 to fool rtld. This should have
been removed some time ago.

Fix the namespace pollution caused by iconv.h including stdbool.h
This broke any C89 ports that defined bool themselves, including things
like gcc, gtk, and so on.

The iconv in libc did two things - implement the standard APIs, the GNU
extensions and also tried to be link time compatible with ports libiconv.
This splits that functionality and enables the parts that shouldn't
interfere with the port by default.

WITH_ICONV (now on by default) - adds iconv.h, iconv_open(3) etc.
WITH_LIBICONV_COMPAT (off by default) adds the libiconv_open etc API, linker
symbols and even a stub libiconv.so.3 that are good enough to be able
to 'pkg delete -f libiconv' on a running system and reasonably expect it
to work.

I have tortured many machines over the last few days to try and reduce
the possibilities of foot-shooting as much as I can. I've successfully
recompiled to enable and disable the libiconv_compat modes, ports that use
libiconv alongside system iconv etc. If you don't enable the
WITH_LIBICONV_COMPAT switch, they don't share symbol space.

This is an extension of behavior on other system. iconv(3) is a standard
libc interface and libiconv port expects to be able to run alongside it on
systems that have it.

Bumped osreldate.

Replace the #define for "iconv" so it is for the function name instead of
a macro with parameters. Remove a __DECONST hack and add consts instead
for gnu libiconv API compatability. This makes it work with things like
devel/boost-libs that expects to use "iconv" as though it were a pointer.

Add the BSD-licensed Citrus iconv to the base system with default off
setting. It can be built by setting the WITH_ICONV knob. While this
knob is unset, the library part, the binaries, the header file and
the metadata files will not be built or installed so it makes no impact
on the system if left turned off.

This work is based on the iconv implementation in NetBSD but a great
number of improvements and feature additions have been included:

- Some utilities have been added. There is a conversion table generator,
which can compare conversion tables to reference data generated by
GNU libiconv. This helps ensuring conversion compatibility.
- UTF-16 surrogate support and some endianness issues have been fixed.
- The rather chaotic Makefiles to build metadata have been refactored
and cleaned up, now it is easy to read and it is also easier to add
support for new encodings.
- A bunch of new encodings and encoding aliases have been added.
- Support for 1->2, 1->3 and 1->4 mappings, which is needed for
transliterating with flying accents as GNU does, like "u.
- Lots of warnings have been fixed, the major part of the code is
now WARNS=6 clean.
- New section 1 and section 5 manual pages have been added.
- Some GNU-specific calls have been implemented:
iconvlist(), iconvctl(), iconv_canonicalize(), iconv_open_into()
- Support for GNU's //IGNORE suffix has been added.
- The "-" argument for stdin is now recognized in iconv(1) as per POSIX.
- The Big5 conversion module has been fixed.
- The iconv.h header files is supposed to be compatible with the
GNU version, i.e. sources should build with base iconv.h and
GNU libiconv. It also includes a macro magic to deal with the
char ** and const char ** incompatibility.
- GNU compatibility: "" or "char" means the current local
encoding in use
- Various cleanups and style(9) fixes.

Approved by: delphij (mentor)
Obtained from: The NetBSD Project
Sponsored by: Google Summer of Code 2009