Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC the xlocale implementation.

Merged revisions: 227487,227753,227807,227818,227999,228002,228875,230156,231673,232498,232601,232620,232626,232926-232927,232929,232931,232935,233173,233600,234573,234578,235239

This currently defines __NO_TLS on ARM (unlike head), because the required
support function has not been MFC'd.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

* style(9)'fy
* declare prototype for __time_load_locale() in timelocal.h

Relax local FreeBSD restrictions on 3 chars abbrev. name length and %c format
since they not allows POSIXly legal locale data. Currently, if relaxed form
POSIXly legal locale data will be used right now, some programs will be broken,
but it means that either locale data or programs must be fixed, not the library.

Introduce non-standard md_order (month/day order) locale field to be used later
via nl_langinfo(). Currently %EF and %Ef emulated using this field, but they
planned for remove in future in favour of nl_langinfo() test field.

Implement %F per POSIX

Implement ampm_fmt (%r) per POSIX

Hardcode c_fmt in a different way since used in nl_langinfo now

Export internal data structures in same manner as numeric/monetary/messages
structures exported.
Protect timelocal.h from multiple inclusions.

Treat c_fmt field as compatibility placeholder

%Ex -> %Ef to not conflict with POSIX
Add %EF (long months name / day order)
Check that O and E not intermixed
Add missing POSIX extension to example

Add %Ex extension to determine "%e %b" or "%b %e" order
Separate alternative for O and E cases

Implement new format specifier for strftime: %OB, alternative national
representation of the full month name. In the Russian locale, this alternative
will be "nominative case", useful when the date designate month as a whole.
E.g. month heading in a calendar. I hope it can be useful for some other
locales too.

Discussed with: wollman, ache

$Id$ -> $FreeBSD$

Import strptime(3) into libc. We've got permission by Kevin Ruddy to
modify the original `no modifications' copyright message, and i've
included his mail into the source file.

The common localization functions between strptime(3) and strftime(3)
have been broken out into timelocal.[ch].