[RFC][PATCH v6 00/16][BZ 10871] Month names in genitive case

[Rafal Luzynski <digitalfreak at lingonborough dot com>]

Hello,

This is the new set of patches.

First of all, this time I'm not posting all patches of the set.  Some
of them have not changed, some contain only locale data which provide
only noise.  Those who want to see all patches please see:

* bugzilla: https://sourceware.org/bugzilla/show_bug.cgi?id=10871
* my GitHub repo: https://github.com/rluzynski/glibc

Also for those brave enough there is a copr repository containing compiled
glibc binaries for any modern Fedora.  These builds have all patches
applied, including those not posted here, but excluding the backward
compatibility patches.  Otherwise you would not see any changes in the
applications unless you recompiled them from the source code.  The effect
you will see when you install binaries from my copr repo is the same as
you will see in the future glibc version:

* when the applications are recompiled from source without any changes;
* or if the glibc maintainers decide that the backward compatibility is
  not needed because this means maintaining the old bug.

Please test and help me spot which applications display dates incorrectly
because of these changes.  Also please note how many finally display dates
correctly.

Main differences between the old set of patches and this one:

* alt_mon section is optional in the locale data source script
  (revert the change from the previous patch set);
* missing alt_mon section is generated as a copy of mon by localedef;
* comments reworded not to suggest that ALTMON_x and "%OB" are standalone
  (nominative) and MON_x and "%B" are for the full date format (genitive),
  this will be decided later (although I still promote this approach);
* ab_alt_mon (abbreviated alternative month name) and "%Ob" format specifier
  also implemented, there are at least 2 languages which need this
  (Belarusian and Russian), this is a sufficient reason to implement it;
* all version-dependent code rebased from glibc 2.25 to 2.26.

Enjoy!