gettext*: update to 0.22

Version 0.22 - June 2023

* PO file format:
  - When a #: line contains references to file names that contain spaces,
    these file names are surrounded by Unicode characters U+2068 and U+2069.
    This makes it possible to parse such references correctly.

* Improvements for maintainers:
  - The AM_GNU_GETTEXT macro now defines two variables localedir_c and
    localedir_c_make, that can be used in C code or in Makefiles,
    respectively, for representing the value of the --localedir configure
    option.

* Programming languages support:
  - C, C++:
    o xgettext now supports gettext-like functions that take wide strings
      (of type 'const wchar_t *', 'const char16_t *', or 'const char32_t *')
      as arguments.
    o xgettext now recognizes numbers with digit separators, as defined by
      ISO C 23, as tokens.
    o xgettext and msgfmt now recognize the format string directive %b
      (for binary integer output, as defined by ISO C 23) in format strings.
    o xgettext and msgfmt now recognize the argument size specifiers
      w8, w16, w32, w64, wf8, wf16, wf32, wf64 (as defined by ISO C 23)
      in format strings.
    o xgettext and msgfmt now recognize C++ format strings, as defined by
      ISO C++ 20.  They are marked as 'c++-format' in POT and PO files.
      A new example has been added, 'hello-c++20', that illustrates how
      to use these format strings with gettext.
  - Java:
    o The build system and tools now also support Java versions newer than
      Java 11. This is known to work up to Java 20, at least. On the other
      hand, support for old versions of Java (Java 1.5 and GCJ) has been
      dropped.
  - Tcl: xgettext now supports the \x, \u, and \U escapes as defined in
    Tcl 8.6.

* Portability:
  - On systems with musl libc, the *gettext() functions in libc now work
    with MO files generated from PO files with an encoding other than UTF-8.
    To this effect, the msgfmt program now converts the messages to UTF-8
    encoding before storing them in a MO file.  You can prevent this by
    using the msgfmt --no-convert option.
  - On systems with musl libc, the *gettext() functions in libc now work
    with MO files generated from PO files with ISO C 99 <inttypes.h> format
    string directive macros.  To this effect, the msgfmt program pre-expands
    strings with such macros.  You can prevent this by using the msgfmt
    --no-redundancy option.

* xgettext:
  - The xgettext option '--sorted-output' is now deprecated.
  - xgettext input files of type PO that are not all ASCII and not UTF-8
    encoded are now handled correctly.

* The base Unicode standard is now updated to 15.0.0.

* Emacs PO mode:
  Fix an incompatibility with Emacs version 29 or newer.


(wiz)