Update to 0.20.1

Changelog:
Version 0.20.1 - May 2019

* Important bug fix:
  - Fixed a wrong shared library versioning of libintl.so.

Version 0.20 - May 2019

* Support for reproducible builds:
  - msgfmt now eliminates the POT-Creation-Date header field from .mo files.

* Improvements for translators:
  - update-po target in Makefile.in.in now uses msgmerge --previous.

* Improvements for maintainers:
  - msgmerge now has an option --for-msgfmt, that produces a PO file meant
    for use by msgfmt only.  This option saves processing time, in particular
    by omitting fuzzy matching that is not useful in this situation.
  - The .pot file in a 'po' directory is now erased by "make maintainer-clean".
  - It is now possible to override xgettext options from the po/Makefile.in.in
    through options in XGETTEXT_OPTIONS (declared in po/Makevars).
  - The --intl option of the gettextize program (deprecated since 2010) is
    no longer available. Instead of including the intl sources in your package,
    we suggest making the libintl library an optional prerequisite of your
    package. This will simplify the build system of your package.
  - Accordingly, the Autoconf macro AM_GNU_GETTEXT_INTL_SUBDIR is gone as well.

* Programming languages support:
  - C, C++:
    xgettext now supports strings in u8"..." syntax, as specified in C11
    and C++11.
  - C, C++:
    xgettext now supports 'p'/'P' exponent markers in number tokens, as
    specified in C99 and C++17.
  - C++:
    xgettext now supports underscores in number tokens.
  - C++:
    xgettext now supports single-quotes in number tokens, as specified in
    C++14.
  - Shell:
    o The programs 'gettext', 'ngettext' now support a --context argument.
    o gettext.sh contains new function eval_pgettext and eval_npgettext
      for producing translations of messages with context.
  - Java:
    o xgettext now supports UTF-8 encoded .properties files (a new feature
      of Java 9).
    o The build system and tools now support Java 9, 10, and 11. On the
      other hand, support for old versions of Java (Java 5 and older,
      GCJ 4.2.x and older) has been dropped.
  - Perl:
    o Native support for context functions (pgettext, dpgettext, dcpgettext,
      npgettext, dnpgettext, dcnpgettext).
    o better detection of question mark and slash as operators (as opposed
      to regular expression delimiters).
  - Scheme:
    xgettext now parses the syntax for specialized byte vectors (#u8(...),
    #vu8(...), etc.) correctly.
  - Pascal:
    xgettext can now extract strings from .rsj files, produced by the
    Free Pascal compiler version 3.0.0 or newer.
  - Vala:
    xgettext now parses escape sequences in strings more accurately.
  - JavaScript:
    xgettext now parses template literals correctly.

* Runtime behaviour:
  - The interpretation of the language preferences on macOS has been fixed.
  - Per-thread locales are now also supported on Solaris 11.4.
  - The replacements for the printf()/fprintf()/... functions that are
    provided through <libintl.h> on native Windows and NetBSD are now POSIX
    compliant.  There is no conflict any more between these replacements
    and other possible replacements provided by gnulib or mingw.

* Libtextstyle:
  - This package installs a new library 'libtextstyle', together with a new
    header file <textstyle.h>.  It is a library for styling text output sent
    to a console or terminal emulator.
    Packagers: please see the suggested packaging hints in the file PACKAGING.


(ryoon)